-8c2=-800

Solution for -8c2=-800 equation:

-8c^2=-800

We move all terms to the left:

-8c^2-(-800)=0

We add all the numbers together, and all the variables

-8c^2+800=0

a = -8; b = 0; c = +800;
Δ = b2-4ac
Δ = 02-4·(-8)·800
Δ = 25600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{25600}=160$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-160}{2*-8}=\frac{-160}{-16}
=+10
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+160}{2*-8}=\frac{160}{-16}
=-10
$