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a*x^3+b*x^2+c*x+d=0 equation

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   3      2              
a*x  + b*x  + c*x + d = 0
$$a x^{3} + b x^{2} + c x + d = 0$$
Vieta's Theorem
rewrite the equation
$$a x^{3} + b x^{2} + c x + d = 0$$
of
$$a x^{3} + b x^{2} + c x + d = 0$$
as reduced cubic equation
$$x^{3} + \frac{b x^{2}}{a} + \frac{c x}{a} + \frac{d}{a} = 0$$
$$\frac{a x^{3} + b x^{2} + c x + d}{a} = 0$$
$$p x^{2} + x^{3} + q x + v = 0$$
where
$$p = \frac{b}{a}$$
$$p = \frac{b}{a}$$
$$q = \frac{c}{a}$$
$$q = \frac{c}{a}$$
$$v = \frac{d}{a}$$
$$v = \frac{d}{a}$$
Vieta Formulas
$$x_{1} + x_{2} + x_{3} = - p$$
$$x_{1} x_{2} + x_{1} x_{3} + x_{2} x_{3} = q$$
$$x_{1} x_{2} x_{3} = v$$
$$x_{1} + x_{2} + x_{3} = - \frac{b}{a}$$
$$x_{1} x_{2} + x_{1} x_{3} + x_{2} x_{3} = \frac{c}{a}$$
$$x_{1} x_{2} x_{3} = \frac{d}{a}$$
The graph
Rapid solution [src]
                   _____________________________________________________________________                                                                                           
                  /        ________________________________________                                                                                                                
                 /        /                      2               3                                                                                                                 
                /        /  /   3               \      / 2      \                                                                                                                  
               /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                  
              /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                  
             /        /     |  3     a        2 |      | 2    a |      3                                                               2                                           
            /       \/      \ a              a  /      \a       /     b    27*d   9*b*c                                               b    3*c                                     
           /        ----------------------------------------------- + -- + ---- - -----                                               -- - ---                                     
        3 /                                2                           3   2*a        2                                                2    a                                      
        \/                                                            a            2*a      b                                         a                                            
x_1 = - -------------------------------------------------------------------------------- - --- - ----------------------------------------------------------------------------------
                                               3                                           3*a                _____________________________________________________________________
                                                                                                             /        ________________________________________                     
                                                                                                            /        /                      2               3                      
                                                                                                           /        /  /   3               \      / 2      \                       
                                                                                                          /        /   |2*b    27*d   9*b*c|      |b    3*c|                       
                                                                                                         /        /    |---- + ---- - -----|  - 4*|-- - ---|                       
                                                                                                        /        /     |  3     a        2 |      | 2    a |      3                
                                                                                                       /       \/      \ a              a  /      \a       /     b    27*d   9*b*c 
                                                                                                 3*   /        ----------------------------------------------- + -- + ---- - ----- 
                                                                                                   3 /                                2                           3   2*a        2 
                                                                                                   \/                                                            a            2*a  
$$x_{1} = - \frac{\sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}}{3} - \frac{- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}}{3 \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}} - \frac{b}{3 a}$$
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                        /        ________________________________________                                                                                                                                          
                       /        /                      2               3                                                                                                                                           
                      /        /  /   3               \      / 2      \                                                                                                                                            
                     /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                                            
                    /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                                            
                   /        /     |  3     a        2 |      | 2    a |      3                 /          ___\                                                 2                                                   
                  /       \/      \ a              a  /      \a       /     b    27*d   9*b*c  |  1   I*\/ 3 |                                                b    3*c                                             
                 /        ----------------------------------------------- + -- + ---- - ----- *|- - - -------|                                                -- - ---                                             
              3 /                                2                           3   2*a        2  \  2      2   /                                                 2    a                                              
         b    \/                                                            a            2*a                                                                  a                                                    
x_2 = - --- - ------------------------------------------------------------------------------------------------ - --------------------------------------------------------------------------------------------------
        3*a                                                  3                                                                                _____________________________________________________________________
                                                                                                                                             /        ________________________________________                     
                                                                                                                                            /        /                      2               3                      
                                                                                                                                           /        /  /   3               \      / 2      \                       
                                                                                                                                          /        /   |2*b    27*d   9*b*c|      |b    3*c|                       
                                                                                                                                         /        /    |---- + ---- - -----|  - 4*|-- - ---|                       
                                                                                                                   /          ___\      /        /     |  3     a        2 |      | 2    a |      3                
                                                                                                                   |  1   I*\/ 3 |     /       \/      \ a              a  /      \a       /     b    27*d   9*b*c 
                                                                                                                 3*|- - - -------|*   /        ----------------------------------------------- + -- + ---- - ----- 
                                                                                                                   \  2      2   / 3 /                                2                           3   2*a        2 
                                                                                                                                   \/                                                            a            2*a  
$$x_{2} = - \frac{\left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}}{3} - \frac{- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}}{3 \left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}} - \frac{b}{3 a}$$
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                        /        ________________________________________                                                                                                                                          
                       /        /                      2               3                                                                                                                                           
                      /        /  /   3               \      / 2      \                                                                                                                                            
                     /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                                            
                    /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                                            
                   /        /     |  3     a        2 |      | 2    a |      3                 /          ___\                                                 2                                                   
                  /       \/      \ a              a  /      \a       /     b    27*d   9*b*c  |  1   I*\/ 3 |                                                b    3*c                                             
                 /        ----------------------------------------------- + -- + ---- - ----- *|- - + -------|                                                -- - ---                                             
              3 /                                2                           3   2*a        2  \  2      2   /                                                 2    a                                              
         b    \/                                                            a            2*a                                                                  a                                                    
x_3 = - --- - ------------------------------------------------------------------------------------------------ - --------------------------------------------------------------------------------------------------
        3*a                                                  3                                                                                _____________________________________________________________________
                                                                                                                                             /        ________________________________________                     
                                                                                                                                            /        /                      2               3                      
                                                                                                                                           /        /  /   3               \      / 2      \                       
                                                                                                                                          /        /   |2*b    27*d   9*b*c|      |b    3*c|                       
                                                                                                                                         /        /    |---- + ---- - -----|  - 4*|-- - ---|                       
                                                                                                                   /          ___\      /        /     |  3     a        2 |      | 2    a |      3                
                                                                                                                   |  1   I*\/ 3 |     /       \/      \ a              a  /      \a       /     b    27*d   9*b*c 
                                                                                                                 3*|- - + -------|*   /        ----------------------------------------------- + -- + ---- - ----- 
                                                                                                                   \  2      2   / 3 /                                2                           3   2*a        2 
                                                                                                                                   \/                                                            a            2*a  
$$x_{3} = - \frac{\left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}}{3} - \frac{- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}}{3 \left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}} - \frac{b}{3 a}$$
Sum and product of roots [src]
sum
             _____________________________________________________________________                                                                                                                 _____________________________________________________________________                                                                                                                                           _____________________________________________________________________                                                                                                                     
            /        ________________________________________                                                                                                                                     /        ________________________________________                                                                                                                                                               /        ________________________________________                                                                                                                                          
           /        /                      2               3                                                                                                                                     /        /                      2               3                                                                                                                                                               /        /                      2               3                                                                                                                                           
          /        /  /   3               \      / 2      \                                                                                                                                     /        /  /   3               \      / 2      \                                                                                                                                                               /        /  /   3               \      / 2      \                                                                                                                                            
         /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                                    /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                                                              /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                                            
        /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                                   /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                                                             /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                                            
       /        /     |  3     a        2 |      | 2    a |      3                                                               2                                                           /        /     |  3     a        2 |      | 2    a |      3                 /          ___\                                                 2                                                                   /        /     |  3     a        2 |      | 2    a |      3                 /          ___\                                                 2                                                   
      /       \/      \ a              a  /      \a       /     b    27*d   9*b*c                                               b    3*c                                                    /       \/      \ a              a  /      \a       /     b    27*d   9*b*c  |  1   I*\/ 3 |                                                b    3*c                                                            /       \/      \ a              a  /      \a       /     b    27*d   9*b*c  |  1   I*\/ 3 |                                                b    3*c                                             
     /        ----------------------------------------------- + -- + ---- - -----                                               -- - ---                                                   /        ----------------------------------------------- + -- + ---- - ----- *|- - - -------|                                                -- - ---                                                           /        ----------------------------------------------- + -- + ---- - ----- *|- - + -------|                                                -- - ---                                             
  3 /                                2                           3   2*a        2                                                2    a                                                 3 /                                2                           3   2*a        2  \  2      2   /                                                 2    a                                                         3 /                                2                           3   2*a        2  \  2      2   /                                                 2    a                                              
  \/                                                            a            2*a      b                                         a                                                  b    \/                                                            a            2*a                                                                  a                                                          b    \/                                                            a            2*a                                                                  a                                                    
- -------------------------------------------------------------------------------- - --- - ---------------------------------------------------------------------------------- + - --- - ------------------------------------------------------------------------------------------------ - -------------------------------------------------------------------------------------------------- + - --- - ------------------------------------------------------------------------------------------------ - --------------------------------------------------------------------------------------------------
                                         3                                           3*a                _____________________________________________________________________     3*a                                                  3                                                                                _____________________________________________________________________     3*a                                                  3                                                                                _____________________________________________________________________
                                                                                                       /        ________________________________________                                                                                                                                                               /        ________________________________________                                                                                                                                                               /        ________________________________________                     
                                                                                                      /        /                      2               3                                                                                                                                                               /        /                      2               3                                                                                                                                                               /        /                      2               3                      
                                                                                                     /        /  /   3               \      / 2      \                                                                                                                                                               /        /  /   3               \      / 2      \                                                                                                                                                               /        /  /   3               \      / 2      \                       
                                                                                                    /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                                                              /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                                                              /        /   |2*b    27*d   9*b*c|      |b    3*c|                       
                                                                                                   /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                                                             /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                                                             /        /    |---- + ---- - -----|  - 4*|-- - ---|                       
                                                                                                  /        /     |  3     a        2 |      | 2    a |      3                                                                                                                                /          ___\      /        /     |  3     a        2 |      | 2    a |      3                                                                                                                                /          ___\      /        /     |  3     a        2 |      | 2    a |      3                
                                                                                                 /       \/      \ a              a  /      \a       /     b    27*d   9*b*c                                                                                                                 |  1   I*\/ 3 |     /       \/      \ a              a  /      \a       /     b    27*d   9*b*c                                                                                                                 |  1   I*\/ 3 |     /       \/      \ a              a  /      \a       /     b    27*d   9*b*c 
                                                                                           3*   /        ----------------------------------------------- + -- + ---- - -----                                                                                                               3*|- - - -------|*   /        ----------------------------------------------- + -- + ---- - -----                                                                                                               3*|- - + -------|*   /        ----------------------------------------------- + -- + ---- - ----- 
                                                                                             3 /                                2                           3   2*a        2                                                                                                                 \  2      2   / 3 /                                2                           3   2*a        2                                                                                                                 \  2      2   / 3 /                                2                           3   2*a        2 
                                                                                             \/                                                            a            2*a                                                                                                                                  \/                                                            a            2*a                                                                                                                                  \/                                                            a            2*a  
$$\left(- \frac{\sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}}{3} - \frac{- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}}{3 \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}} - \frac{b}{3 a}\right) + \left(- \frac{\left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}}{3} - \frac{- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}}{3 \left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}} - \frac{b}{3 a}\right) + \left(- \frac{\left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}}{3} - \frac{- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}}{3 \left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}} - \frac{b}{3 a}\right)$$
=
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            /        ________________________________________                                                                                                                           /        ________________________________________                                                  /        ________________________________________                                                                                                                                                                                                                                               
           /        /                      2               3                                                                                                                           /        /                      2               3                                                  /        /                      2               3                                                                                                                                                                                                                                                
          /        /  /   3               \      / 2      \                                                                                                                           /        /  /   3               \      / 2      \                                                  /        /  /   3               \      / 2      \                                                                                                                                                                                                                                                 
         /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                          /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                 /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                                                                                                                                                 
        /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                         /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                                                                                                                                                 
       /        /     |  3     a        2 |      | 2    a |      3                                                             2                                                   /        /     |  3     a        2 |      | 2    a |      3                 /          ___\        /        /     |  3     a        2 |      | 2    a |      3                 /          ___\                                                 2                                                                                                    2                                                   
      /       \/      \ a              a  /      \a       /     b    27*d   9*b*c                                             b    3*c                                            /       \/      \ a              a  /      \a       /     b    27*d   9*b*c  |  1   I*\/ 3 |       /       \/      \ a              a  /      \a       /     b    27*d   9*b*c  |  1   I*\/ 3 |                                                b    3*c                                                                                             b    3*c                                             
     /        ----------------------------------------------- + -- + ---- - -----                                             -- - ---                                           /        ----------------------------------------------- + -- + ---- - ----- *|- - + -------|      /        ----------------------------------------------- + -- + ---- - ----- *|- - - -------|                                                -- - ---                                                                                             -- - ---                                             
  3 /                                2                           3   2*a        2                                              2    a                                         3 /                                2                           3   2*a        2  \  2      2   /   3 /                                2                           3   2*a        2  \  2      2   /                                                 2    a                                                                                               2    a                                              
  \/                                                            a            2*a     b                                        a                                               \/                                                            a            2*a                     \/                                                            a            2*a                                                                  a                                                                                                    a                                                    
- -------------------------------------------------------------------------------- - - - ---------------------------------------------------------------------------------- - ------------------------------------------------------------------------------------------------ - ------------------------------------------------------------------------------------------------ - -------------------------------------------------------------------------------------------------- - --------------------------------------------------------------------------------------------------
                                         3                                           a                _____________________________________________________________________                                                  3                                                                                                  3                                                                                _____________________________________________________________________                                _____________________________________________________________________
                                                                                                     /        ________________________________________                                                                                                                                                                                                                                                          /        ________________________________________                                                    /        ________________________________________                     
                                                                                                    /        /                      2               3                                                                                                                                                                                                                                                          /        /                      2               3                                                    /        /                      2               3                      
                                                                                                   /        /  /   3               \      / 2      \                                                                                                                                                                                                                                                          /        /  /   3               \      / 2      \                                                    /        /  /   3               \      / 2      \                       
                                                                                                  /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                                                                                                                                                         /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                   /        /   |2*b    27*d   9*b*c|      |b    3*c|                       
                                                                                                 /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                                                                                                                                                        /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                  /        /    |---- + ---- - -----|  - 4*|-- - ---|                       
                                                                                                /        /     |  3     a        2 |      | 2    a |      3                                                                                                                                                                                                                           /          ___\      /        /     |  3     a        2 |      | 2    a |      3                     /          ___\      /        /     |  3     a        2 |      | 2    a |      3                
                                                                                               /       \/      \ a              a  /      \a       /     b    27*d   9*b*c                                                                                                                                                                                                            |  1   I*\/ 3 |     /       \/      \ a              a  /      \a       /     b    27*d   9*b*c      |  1   I*\/ 3 |     /       \/      \ a              a  /      \a       /     b    27*d   9*b*c 
                                                                                         3*   /        ----------------------------------------------- + -- + ---- - -----                                                                                                                                                                                                          3*|- - + -------|*   /        ----------------------------------------------- + -- + ---- - -----    3*|- - - -------|*   /        ----------------------------------------------- + -- + ---- - ----- 
                                                                                           3 /                                2                           3   2*a        2                                                                                                                                                                                                            \  2      2   / 3 /                                2                           3   2*a        2      \  2      2   / 3 /                                2                           3   2*a        2 
                                                                                           \/                                                            a            2*a                                                                                                                                                                                                                             \/                                                            a            2*a                       \/                                                            a            2*a  
$$- \frac{\sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}}{3} - \frac{\left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}}{3} - \frac{\left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}}{3} - \frac{- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}}{3 \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}} - \frac{- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}}{3 \left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}} - \frac{- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}}{3 \left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}} - \frac{b}{a}$$
product
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            /        ________________________________________                                                                                                                                     /        ________________________________________                                                                                                                                                               /        ________________________________________                                                                                                                                          
           /        /                      2               3                                                                                                                                     /        /                      2               3                                                                                                                                                               /        /                      2               3                                                                                                                                           
          /        /  /   3               \      / 2      \                                                                                                                                     /        /  /   3               \      / 2      \                                                                                                                                                               /        /  /   3               \      / 2      \                                                                                                                                            
         /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                                    /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                                                              /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                                            
        /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                                   /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                                                             /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                                            
       /        /     |  3     a        2 |      | 2    a |      3                                                               2                                                           /        /     |  3     a        2 |      | 2    a |      3                 /          ___\                                                 2                                                                   /        /     |  3     a        2 |      | 2    a |      3                 /          ___\                                                 2                                                   
      /       \/      \ a              a  /      \a       /     b    27*d   9*b*c                                               b    3*c                                                    /       \/      \ a              a  /      \a       /     b    27*d   9*b*c  |  1   I*\/ 3 |                                                b    3*c                                                            /       \/      \ a              a  /      \a       /     b    27*d   9*b*c  |  1   I*\/ 3 |                                                b    3*c                                             
     /        ----------------------------------------------- + -- + ---- - -----                                               -- - ---                                                   /        ----------------------------------------------- + -- + ---- - ----- *|- - - -------|                                                -- - ---                                                           /        ----------------------------------------------- + -- + ---- - ----- *|- - + -------|                                                -- - ---                                             
  3 /                                2                           3   2*a        2                                                2    a                                                 3 /                                2                           3   2*a        2  \  2      2   /                                                 2    a                                                         3 /                                2                           3   2*a        2  \  2      2   /                                                 2    a                                              
  \/                                                            a            2*a      b                                         a                                                  b    \/                                                            a            2*a                                                                  a                                                          b    \/                                                            a            2*a                                                                  a                                                    
- -------------------------------------------------------------------------------- - --- - ---------------------------------------------------------------------------------- * - --- - ------------------------------------------------------------------------------------------------ - -------------------------------------------------------------------------------------------------- * - --- - ------------------------------------------------------------------------------------------------ - --------------------------------------------------------------------------------------------------
                                         3                                           3*a                _____________________________________________________________________     3*a                                                  3                                                                                _____________________________________________________________________     3*a                                                  3                                                                                _____________________________________________________________________
                                                                                                       /        ________________________________________                                                                                                                                                               /        ________________________________________                                                                                                                                                               /        ________________________________________                     
                                                                                                      /        /                      2               3                                                                                                                                                               /        /                      2               3                                                                                                                                                               /        /                      2               3                      
                                                                                                     /        /  /   3               \      / 2      \                                                                                                                                                               /        /  /   3               \      / 2      \                                                                                                                                                               /        /  /   3               \      / 2      \                       
                                                                                                    /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                                                              /        /   |2*b    27*d   9*b*c|      |b    3*c|                                                                                                                                                              /        /   |2*b    27*d   9*b*c|      |b    3*c|                       
                                                                                                   /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                                                             /        /    |---- + ---- - -----|  - 4*|-- - ---|                                                                                                                                                             /        /    |---- + ---- - -----|  - 4*|-- - ---|                       
                                                                                                  /        /     |  3     a        2 |      | 2    a |      3                                                                                                                                /          ___\      /        /     |  3     a        2 |      | 2    a |      3                                                                                                                                /          ___\      /        /     |  3     a        2 |      | 2    a |      3                
                                                                                                 /       \/      \ a              a  /      \a       /     b    27*d   9*b*c                                                                                                                 |  1   I*\/ 3 |     /       \/      \ a              a  /      \a       /     b    27*d   9*b*c                                                                                                                 |  1   I*\/ 3 |     /       \/      \ a              a  /      \a       /     b    27*d   9*b*c 
                                                                                           3*   /        ----------------------------------------------- + -- + ---- - -----                                                                                                               3*|- - - -------|*   /        ----------------------------------------------- + -- + ---- - -----                                                                                                               3*|- - + -------|*   /        ----------------------------------------------- + -- + ---- - ----- 
                                                                                             3 /                                2                           3   2*a        2                                                                                                                 \  2      2   / 3 /                                2                           3   2*a        2                                                                                                                 \  2      2   / 3 /                                2                           3   2*a        2 
                                                                                             \/                                                            a            2*a                                                                                                                                  \/                                                            a            2*a                                                                                                                                  \/                                                            a            2*a  
$$\left(- \frac{\sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}}{3} - \frac{- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}}{3 \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}} - \frac{b}{3 a}\right) * \left(- \frac{\left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}}{3} - \frac{- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}}{3 \left(- \frac{1}{2} - \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}} - \frac{b}{3 a}\right) * \left(- \frac{\left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}}{3} - \frac{- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}}{3 \left(- \frac{1}{2} + \frac{\sqrt{3} i}{2}\right) \sqrt[3]{\frac{\sqrt{- 4 \left(- \frac{3 c}{a} + \frac{b^{2}}{a^{2}}\right)^{3} + \left(\frac{27 d}{a} - \frac{9 b c}{a^{2}} + \frac{2 b^{3}}{a^{3}}\right)^{2}}}{2} + \frac{27 d}{2 a} - \frac{9 b c}{2 a^{2}} + \frac{b^{3}}{a^{3}}}} - \frac{b}{3 a}\right)$$
=
-d 
---
 a 
$$- \frac{d}{a}$$