2x2+7=5x2-20

Solution for 2x2+7=5x2-20 equation:

2x^2+7=5x^2-20

We move all terms to the left:

2x^2+7-(5x^2-20)=0

We get rid of parentheses

2x^2-5x^2+20+7=0

We add all the numbers together, and all the variables

-3x^2+27=0

a = -3; b = 0; c = +27;
Δ = b2-4ac
Δ = 02-4·(-3)·27
Δ = 324
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{324}=18$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-18}{2*-3}=\frac{-18}{-6}
=+3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+18}{2*-3}=\frac{18}{-6}
=-3
$