-2x^2-8x=-120

Solution for -2x^2-8x=-120 equation:

-2x^2-8x=-120

We move all terms to the left:

-2x^2-8x-(-120)=0

We add all the numbers together, and all the variables

-2x^2-8x+120=0

a = -2; b = -8; c = +120;
Δ = b2-4ac
Δ = -82-4·(-2)·120
Δ = 1024
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1024}=32$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-32}{2*-2}=\frac{-24}{-4}
=+6
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+32}{2*-2}=\frac{40}{-4}
=-10
$