-2x^2-36x+80=0

Solution for -2x^2-36x+80=0 equation:

-2x^2-36x+80=0

a = -2; b = -36; c = +80;
Δ = b2-4ac
Δ = -362-4·(-2)·80
Δ = 1936
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1936}=44$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-36)-44}{2*-2}=\frac{-8}{-4}
=+2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-36)+44}{2*-2}=\frac{80}{-4}
=-20
$