256.25=x^2

Solution for 256.25=x^2 equation:

256.25=x^2

We move all terms to the left:

256.25-(x^2)=0

We add all the numbers together, and all the variables

-1x^2+256.25=0

a = -1; b = 0; c = +256.25;
Δ = b2-4ac
Δ = 02-4·(-1)·256.25
Δ = 1025
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:

$\sqrt{\Delta}=\sqrt{1025}=\sqrt{25*41}=\sqrt{25}*\sqrt{41}=5\sqrt{41}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-5\sqrt{41}}{2*-1}=\frac{0-5\sqrt{41}}{-2}
=-\frac{5\sqrt{41}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+5\sqrt{41}}{2*-1}=\frac{0+5\sqrt{41}}{-2}
=\frac{5\sqrt{41}}{-2}
$