(x)^2=(18)^2+(87)^2

Solution for (x)^2=(18)^2+(87)^2 equation:

(x)^2=(18)^2+(87)^2

We move all terms to the left:

(x)^2-((18)^2+(87)^2)=0

We add all the numbers together, and all the variables

x^2-7893=0

a = 1; b = 0; c = -7893;
Δ = b2-4ac
Δ = 02-4·1·(-7893)
Δ = 31572
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:

$\sqrt{\Delta}=\sqrt{31572}=\sqrt{36*877}=\sqrt{36}*\sqrt{877}=6\sqrt{877}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-6\sqrt{877}}{2*1}=\frac{0-6\sqrt{877}}{2}
=-\frac{6\sqrt{877}}{2}
=-3\sqrt{877}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+6\sqrt{877}}{2*1}=\frac{0+6\sqrt{877}}{2}
=\frac{6\sqrt{877}}{2}
=3\sqrt{877}
$