Mister Exam

Other calculators


x^3-9x^2+26x+24=0

x^3-9x^2+26x+24=0 equation

The teacher will be very surprised to see your correct solution 😉

v

Numerical solution:

Do search numerical solution at [, ]

The solution

You have entered [src]
 3      2                
x  - 9*x  + 26*x + 24 = 0
$$x^{3} - 9 x^{2} + 26 x + 24 = 0$$
Vieta's Theorem
it is reduced cubic equation
$$p x^{2} + x^{3} + q x + v = 0$$
where
$$p = \frac{b}{a}$$
$$p = -9$$
$$q = \frac{c}{a}$$
$$q = 26$$
$$v = \frac{d}{a}$$
$$v = 24$$
Vieta Formulas
$$x_{1} + x_{2} + x_{3} = - p$$
$$x_{1} x_{2} + x_{1} x_{3} + x_{2} x_{3} = q$$
$$x_{1} x_{2} x_{3} = v$$
$$x_{1} + x_{2} + x_{3} = 9$$
$$x_{1} x_{2} + x_{1} x_{3} + x_{2} x_{3} = 26$$
$$x_{1} x_{2} x_{3} = 24$$
The graph
Sum and product of roots [src]
sum
                                                                  /                         2/3\                                                                     /                       2/3\                                                          
                                                                  |      /          _______\   |                                                                     |    /          _______\   |                                                          
             _________________                              6 ___ |  1   \648 + 3*\/ 46653 /   |                _________________                              6 ___ |1   \648 + 3*\/ 46653 /   |                _________________                         
    3 ___ 3 /         _______              2/3            I*\/ 3 *|- - + ----------------------|       3 ___ 3 /         _______              2/3            I*\/ 3 *|- - ----------------------|       3 ___ 3 /         _______              2/3         
    \/ 3 *\/  216 + \/ 46653              3                       \  2             6           /       \/ 3 *\/  216 + \/ 46653              3                       \2             6           /       \/ 3 *\/  216 + \/ 46653              3            
3 + -------------------------- + ---------------------- + -------------------------------------- + 3 + -------------------------- + ---------------------- + ------------------------------------ + 3 - -------------------------- - ----------------------
                6                     _________________               _________________                            6                     _________________              _________________                           3                     _________________
                                   3 /         _______             3 /         _______                                                3 /         _______            3 /         _______                                               3 /         _______ 
                                 6*\/  216 + \/ 46653              \/  216 + \/ 46653                                               6*\/  216 + \/ 46653             \/  216 + \/ 46653                                              3*\/  216 + \/ 46653  
$$\left(\frac{3^{\frac{2}{3}}}{6 \sqrt[3]{\sqrt{46653} + 216}} + \frac{\sqrt[3]{3} \sqrt[3]{\sqrt{46653} + 216}}{6} + 3 + \frac{\sqrt[6]{3} i \left(- \frac{1}{2} + \frac{\left(3 \sqrt{46653} + 648\right)^{\frac{2}{3}}}{6}\right)}{\sqrt[3]{\sqrt{46653} + 216}}\right) + \left(\frac{3^{\frac{2}{3}}}{6 \sqrt[3]{\sqrt{46653} + 216}} + \frac{\sqrt[3]{3} \sqrt[3]{\sqrt{46653} + 216}}{6} + 3 + \frac{\sqrt[6]{3} i \left(- \frac{\left(3 \sqrt{46653} + 648\right)^{\frac{2}{3}}}{6} + \frac{1}{2}\right)}{\sqrt[3]{\sqrt{46653} + 216}}\right) + \left(- \frac{\sqrt[3]{3} \sqrt[3]{\sqrt{46653} + 216}}{3} - \frac{3^{\frac{2}{3}}}{3 \sqrt[3]{\sqrt{46653} + 216}} + 3\right)$$
=
            /                       2/3\           /                         2/3\
            |    /          _______\   |           |      /          _______\   |
      6 ___ |1   \648 + 3*\/ 46653 /   |     6 ___ |  1   \648 + 3*\/ 46653 /   |
    I*\/ 3 *|- - ----------------------|   I*\/ 3 *|- - + ----------------------|
            \2             6           /           \  2             6           /
9 + ------------------------------------ + --------------------------------------
               _________________                       _________________         
            3 /         _______                     3 /         _______          
            \/  216 + \/ 46653                      \/  216 + \/ 46653           
$$9 + \frac{\sqrt[6]{3} i \left(- \frac{\left(3 \sqrt{46653} + 648\right)^{\frac{2}{3}}}{6} + \frac{1}{2}\right)}{\sqrt[3]{\sqrt{46653} + 216}} + \frac{\sqrt[6]{3} i \left(- \frac{1}{2} + \frac{\left(3 \sqrt{46653} + 648\right)^{\frac{2}{3}}}{6}\right)}{\sqrt[3]{\sqrt{46653} + 216}}$$
product
                                                                  /                         2/3\                                                                     /                       2/3\                                                          
                                                                  |      /          _______\   |                                                                     |    /          _______\   |                                                          
             _________________                              6 ___ |  1   \648 + 3*\/ 46653 /   |                _________________                              6 ___ |1   \648 + 3*\/ 46653 /   |                _________________                         
    3 ___ 3 /         _______              2/3            I*\/ 3 *|- - + ----------------------|       3 ___ 3 /         _______              2/3            I*\/ 3 *|- - ----------------------|       3 ___ 3 /         _______              2/3         
    \/ 3 *\/  216 + \/ 46653              3                       \  2             6           /       \/ 3 *\/  216 + \/ 46653              3                       \2             6           /       \/ 3 *\/  216 + \/ 46653              3            
3 + -------------------------- + ---------------------- + -------------------------------------- * 3 + -------------------------- + ---------------------- + ------------------------------------ * 3 - -------------------------- - ----------------------
                6                     _________________               _________________                            6                     _________________              _________________                           3                     _________________
                                   3 /         _______             3 /         _______                                                3 /         _______            3 /         _______                                               3 /         _______ 
                                 6*\/  216 + \/ 46653              \/  216 + \/ 46653                                               6*\/  216 + \/ 46653             \/  216 + \/ 46653                                              3*\/  216 + \/ 46653  
$$\left(\frac{3^{\frac{2}{3}}}{6 \sqrt[3]{\sqrt{46653} + 216}} + \frac{\sqrt[3]{3} \sqrt[3]{\sqrt{46653} + 216}}{6} + 3 + \frac{\sqrt[6]{3} i \left(- \frac{1}{2} + \frac{\left(3 \sqrt{46653} + 648\right)^{\frac{2}{3}}}{6}\right)}{\sqrt[3]{\sqrt{46653} + 216}}\right) * \left(\frac{3^{\frac{2}{3}}}{6 \sqrt[3]{\sqrt{46653} + 216}} + \frac{\sqrt[3]{3} \sqrt[3]{\sqrt{46653} + 216}}{6} + 3 + \frac{\sqrt[6]{3} i \left(- \frac{\left(3 \sqrt{46653} + 648\right)^{\frac{2}{3}}}{6} + \frac{1}{2}\right)}{\sqrt[3]{\sqrt{46653} + 216}}\right) * \left(- \frac{\sqrt[3]{3} \sqrt[3]{\sqrt{46653} + 216}}{3} - \frac{3^{\frac{2}{3}}}{3 \sqrt[3]{\sqrt{46653} + 216}} + 3\right)$$
=
-24
$$-24$$
Rapid solution [src]
                                                                        /                         2/3\
                                                                        |      /          _______\   |
                   _________________                              6 ___ |  1   \648 + 3*\/ 46653 /   |
          3 ___ 3 /         _______              2/3            I*\/ 3 *|- - + ----------------------|
          \/ 3 *\/  216 + \/ 46653              3                       \  2             6           /
x_1 = 3 + -------------------------- + ---------------------- + --------------------------------------
                      6                     _________________               _________________         
                                         3 /         _______             3 /         _______          
                                       6*\/  216 + \/ 46653              \/  216 + \/ 46653           
$$x_{1} = \frac{3^{\frac{2}{3}}}{6 \sqrt[3]{\sqrt{46653} + 216}} + \frac{\sqrt[3]{3} \sqrt[3]{\sqrt{46653} + 216}}{6} + 3 + \frac{\sqrt[6]{3} i \left(- \frac{1}{2} + \frac{\left(3 \sqrt{46653} + 648\right)^{\frac{2}{3}}}{6}\right)}{\sqrt[3]{\sqrt{46653} + 216}}$$
                                                                        /                       2/3\
                                                                        |    /          _______\   |
                   _________________                              6 ___ |1   \648 + 3*\/ 46653 /   |
          3 ___ 3 /         _______              2/3            I*\/ 3 *|- - ----------------------|
          \/ 3 *\/  216 + \/ 46653              3                       \2             6           /
x_2 = 3 + -------------------------- + ---------------------- + ------------------------------------
                      6                     _________________              _________________        
                                         3 /         _______            3 /         _______         
                                       6*\/  216 + \/ 46653             \/  216 + \/ 46653          
$$x_{2} = \frac{3^{\frac{2}{3}}}{6 \sqrt[3]{\sqrt{46653} + 216}} + \frac{\sqrt[3]{3} \sqrt[3]{\sqrt{46653} + 216}}{6} + 3 + \frac{\sqrt[6]{3} i \left(- \frac{\left(3 \sqrt{46653} + 648\right)^{\frac{2}{3}}}{6} + \frac{1}{2}\right)}{\sqrt[3]{\sqrt{46653} + 216}}$$
                   _________________                         
          3 ___ 3 /         _______              2/3         
          \/ 3 *\/  216 + \/ 46653              3            
x_3 = 3 - -------------------------- - ----------------------
                      3                     _________________
                                         3 /         _______ 
                                       3*\/  216 + \/ 46653  
$$x_{3} = - \frac{\sqrt[3]{3} \sqrt[3]{\sqrt{46653} + 216}}{3} - \frac{3^{\frac{2}{3}}}{3 \sqrt[3]{\sqrt{46653} + 216}} + 3$$
Numerical answer [src]
x1 = 4.86297120224424 - 3.06789587521708*i
x2 = -0.72594240448847
x3 = 4.86297120224424 + 3.06789587521708*i
x3 = 4.86297120224424 + 3.06789587521708*i
The graph
x^3-9x^2+26x+24=0 equation