c^2=18^2+80^2

Solution for c^2=18^2+80^2 equation:

c^2=18^2+80^2

We move all terms to the left:

c^2-(18^2+80^2)=0

We add all the numbers together, and all the variables

c^2-6724=0

a = 1; b = 0; c = -6724;
Δ = b2-4ac
Δ = 02-4·1·(-6724)
Δ = 26896
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{26896}=164$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-164}{2*1}=\frac{-164}{2}
=-82
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+164}{2*1}=\frac{164}{2}
=82
$