ax^3+bx^2+cx+d=0
Let roots be \frac{a}{c},a,ac
Using product of roots...
a^3=\frac{-d}{a}
a=\sqrt[3]{\frac{-d}{a}}
Subbing it back into the equation, as a is a root
a(\sqrt[3]{\frac{-d}{a}})^3+b(\sqrt[3]{\frac{-d}{a}})^2+c(\sqrt[3]{\frac{-d}{a}})+d=0
-d+b\left (...