(x^2-82-8)=0

Solution for (x^2-82-8)=0 equation:

(x^2-82-8)=0

We get rid of parentheses

x^2-82-8=0

We add all the numbers together, and all the variables

x^2-90=0

a = 1; b = 0; c = -90;
Δ = b2-4ac
Δ = 02-4·1·(-90)
Δ = 360
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:

$\sqrt{\Delta}=\sqrt{360}=\sqrt{36*10}=\sqrt{36}*\sqrt{10}=6\sqrt{10}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-6\sqrt{10}}{2*1}=\frac{0-6\sqrt{10}}{2}
=-\frac{6\sqrt{10}}{2}
=-3\sqrt{10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+6\sqrt{10}}{2*1}=\frac{0+6\sqrt{10}}{2}
=\frac{6\sqrt{10}}{2}
=3\sqrt{10}
$