82+42=c2

Solution for 82+42=c2 equation:

82+42=c2

We move all terms to the left:

82+42-(c2)=0

We add all the numbers together, and all the variables

-1c^2+124=0

a = -1; b = 0; c = +124;
Δ = b2-4ac
Δ = 02-4·(-1)·124
Δ = 496
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{496}=\sqrt{16*31}=\sqrt{16}*\sqrt{31}=4\sqrt{31}$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{31}}{2*-1}=\frac{0-4\sqrt{31}}{-2}
=-\frac{4\sqrt{31}}{-2}
=-\frac{2\sqrt{31}}{-1}
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{31}}{2*-1}=\frac{0+4\sqrt{31}}{-2}
=\frac{4\sqrt{31}}{-2}
=\frac{2\sqrt{31}}{-1}
$