99=6x^2

Solution for 99=6x^2 equation:

99=6x^2

We move all terms to the left:

99-(6x^2)=0

a = -6; b = 0; c = +99;
Δ = b2-4ac
Δ = 02-4·(-6)·99
Δ = 2376
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:

$\sqrt{\Delta}=\sqrt{2376}=\sqrt{36*66}=\sqrt{36}*\sqrt{66}=6\sqrt{66}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-6\sqrt{66}}{2*-6}=\frac{0-6\sqrt{66}}{-12}
=-\frac{6\sqrt{66}}{-12}
=-\frac{\sqrt{66}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+6\sqrt{66}}{2*-6}=\frac{0+6\sqrt{66}}{-12}
=\frac{6\sqrt{66}}{-12}
=\frac{\sqrt{66}}{-2}
$