x=10x^2-28x-39

Solution for x=10x^2-28x-39 equation:

x=10x^2-28x-39

We move all terms to the left:

x-(10x^2-28x-39)=0

We get rid of parentheses

-10x^2+x+28x+39=0

We add all the numbers together, and all the variables

-10x^2+29x+39=0

a = -10; b = 29; c = +39;
Δ = b2-4ac
Δ = 292-4·(-10)·39
Δ = 2401
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2401}=49$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(29)-49}{2*-10}=\frac{-78}{-20}
=3+9/10
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(29)+49}{2*-10}=\frac{20}{-20}
=-1
$