216=2x^2

Solution for 216=2x^2 equation:

216=2x^2

We move all terms to the left:

216-(2x^2)=0

a = -2; b = 0; c = +216;
Δ = b2-4ac
Δ = 02-4·(-2)·216
Δ = 1728
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:

$\sqrt{\Delta}=\sqrt{1728}=\sqrt{576*3}=\sqrt{576}*\sqrt{3}=24\sqrt{3}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-24\sqrt{3}}{2*-2}=\frac{0-24\sqrt{3}}{-4}
=-\frac{24\sqrt{3}}{-4}
=-\frac{6\sqrt{3}}{-1}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+24\sqrt{3}}{2*-2}=\frac{0+24\sqrt{3}}{-4}
=\frac{24\sqrt{3}}{-4}
=\frac{6\sqrt{3}}{-1}
$