10^2+8^2=x^2

Solution for 10^2+8^2=x^2 equation:

10^2+8^2=x^2

We move all terms to the left:

10^2+8^2-(x^2)=0

We add all the numbers together, and all the variables

-1x^2+164=0

a = -1; b = 0; c = +164;
Δ = b2-4ac
Δ = 02-4·(-1)·164
Δ = 656
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{656}=\sqrt{16*41}=\sqrt{16}*\sqrt{41}=4\sqrt{41}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{41}}{2*-1}=\frac{0-4\sqrt{41}}{-2}
=-\frac{4\sqrt{41}}{-2}
=-\frac{2\sqrt{41}}{-1}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{41}}{2*-1}=\frac{0+4\sqrt{41}}{-2}
=\frac{4\sqrt{41}}{-2}
=\frac{2\sqrt{41}}{-1}
$