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x^2+6/5-8-x/10=0 equation

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Numerical solution:

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The solution

You have entered [src]
 2   6       x     
x  + - - 8 - -- = 0
     5       10    
$$- \frac{x}{10} + \left(\left(x^{2} + \frac{6}{5}\right) - 8\right) = 0$$
Detail solution
Expand the expression in the equation
$$- \frac{x}{10} + \left(\left(x^{2} + \frac{6}{5}\right) - 8\right) = 0$$
We get the quadratic equation
$$x^{2} - \frac{x}{10} - \frac{34}{5} = 0$$
This equation is of the form
a*x^2 + b*x + c = 0

A quadratic equation can be solved
using the discriminant.
The roots of the quadratic equation:
$$x_{1} = \frac{\sqrt{D} - b}{2 a}$$
$$x_{2} = \frac{- \sqrt{D} - b}{2 a}$$
where D = b^2 - 4*a*c - it is the discriminant.
Because
$$a = 1$$
$$b = - \frac{1}{10}$$
$$c = - \frac{34}{5}$$
, then
D = b^2 - 4 * a * c = 

(-1/10)^2 - 4 * (1) * (-34/5) = 2721/100

Because D > 0, then the equation has two roots.
x1 = (-b + sqrt(D)) / (2*a)

x2 = (-b - sqrt(D)) / (2*a)

or
$$x_{1} = \frac{1}{20} + \frac{\sqrt{2721}}{20}$$
$$x_{2} = \frac{1}{20} - \frac{\sqrt{2721}}{20}$$
Vieta's Theorem
it is reduced quadratic equation
$$p x + q + x^{2} = 0$$
where
$$p = \frac{b}{a}$$
$$p = - \frac{1}{10}$$
$$q = \frac{c}{a}$$
$$q = - \frac{34}{5}$$
Vieta Formulas
$$x_{1} + x_{2} = - p$$
$$x_{1} x_{2} = q$$
$$x_{1} + x_{2} = \frac{1}{10}$$
$$x_{1} x_{2} = - \frac{34}{5}$$
The graph
Sum and product of roots [src]
sum
       ______          ______
1    \/ 2721    1    \/ 2721 
-- - -------- + -- + --------
20      20      20      20   
$$\left(\frac{1}{20} - \frac{\sqrt{2721}}{20}\right) + \left(\frac{1}{20} + \frac{\sqrt{2721}}{20}\right)$$
=
1/10
$$\frac{1}{10}$$
product
/       ______\ /       ______\
|1    \/ 2721 | |1    \/ 2721 |
|-- - --------|*|-- + --------|
\20      20   / \20      20   /
$$\left(\frac{1}{20} - \frac{\sqrt{2721}}{20}\right) \left(\frac{1}{20} + \frac{\sqrt{2721}}{20}\right)$$
=
-34/5
$$- \frac{34}{5}$$
-34/5
Rapid solution [src]
            ______
     1    \/ 2721 
x1 = -- - --------
     20      20   
$$x_{1} = \frac{1}{20} - \frac{\sqrt{2721}}{20}$$
            ______
     1    \/ 2721 
x2 = -- + --------
     20      20   
$$x_{2} = \frac{1}{20} + \frac{\sqrt{2721}}{20}$$
x2 = 1/20 + sqrt(2721)/20
Numerical answer [src]
x1 = 2.658160271149
x2 = -2.558160271149
x2 = -2.558160271149