3x^2-6x-3=90

Solution for 3x^2-6x-3=90 equation:

3x^2-6x-3=90

We move all terms to the left:

3x^2-6x-3-(90)=0

We add all the numbers together, and all the variables

3x^2-6x-93=0

a = 3; b = -6; c = -93;
Δ = b2-4ac
Δ = -62-4·3·(-93)
Δ = 1152
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:

$\sqrt{\Delta}=\sqrt{1152}=\sqrt{576*2}=\sqrt{576}*\sqrt{2}=24\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-6)-24\sqrt{2}}{2*3}=\frac{6-24\sqrt{2}}{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-6)+24\sqrt{2}}{2*3}=\frac{6+24\sqrt{2}}{6}
$