Cubic equation f=a x+b x^2+c x^3
Solving:
A=\frac{-(a b+9 c f)+\sqrt{(a b+9 c f)^2-4 \left(b^2-3 a c\right) \left(a^2+3 b f\right)}}{2 \left(b^2-3 a c\right)}
G=a+2 b A+3 c A^2
H=a A+b A^2+c A^3-f
F=G^3-27cH^2
B=\left\{F^{1/3}\,,-(-1)^{1/3} F^{1/3}\,,(-1)^{2/3}F^{1/3}\right\}...