S^3+3*x^2-X-3=0

Solution for S^3+3*x^2-X-3=0 equation:

^3+3S^2-S-3=0

We add all the numbers together, and all the variables

3S^2-1S=0

a = 3; b = -1; c = 0;
Δ = b2-4ac
Δ = -12-4·3·0
Δ = 1
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$S_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$S_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1}=1$
$S_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1)-1}{2*3}=\frac{0}{6}
=0
$
$S_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+1}{2*3}=\frac{2}{6}
=1/3
$