621=x^2

Solution for 621=x^2 equation:

621=x^2

We move all terms to the left:

621-(x^2)=0

We add all the numbers together, and all the variables

-1x^2+621=0

a = -1; b = 0; c = +621;
Δ = b2-4ac
Δ = 02-4·(-1)·621
Δ = 2484
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:

$\sqrt{\Delta}=\sqrt{2484}=\sqrt{36*69}=\sqrt{36}*\sqrt{69}=6\sqrt{69}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-6\sqrt{69}}{2*-1}=\frac{0-6\sqrt{69}}{-2}
=-\frac{6\sqrt{69}}{-2}
=-\frac{3\sqrt{69}}{-1}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+6\sqrt{69}}{2*-1}=\frac{0+6\sqrt{69}}{-2}
=\frac{6\sqrt{69}}{-2}
=\frac{3\sqrt{69}}{-1}
$