-2x^2=13x+20

Solution for -2x^2=13x+20 equation:

-2x^2=13x+20

We move all terms to the left:

-2x^2-(13x+20)=0

We get rid of parentheses

-2x^2-13x-20=0

a = -2; b = -13; c = -20;
Δ = b2-4ac
Δ = -132-4·(-2)·(-20)
Δ = 9
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{9}=3$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-13)-3}{2*-2}=\frac{10}{-4}
=-2+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-13)+3}{2*-2}=\frac{16}{-4}
=-4
$