$$4x^3+18x^2+20x+8 = 0$$
Answer
$$ \begin{matrix}x_1 = -3.09219 & x_2 = -0.7039+0.38899i & x_3 = -0.7039-0.38899i \end{matrix} $$
Explanation
This polynomial has no rational roots that can be found using Rational Root Test.
Roots were found using qubic formulas.
This page was created using
Polynomial Equations Solver