$$x^3+4x^2-4x+16 = 0$$
Answer
$$ \begin{matrix}x_1 = -5.31793 & x_2 = 0.65897+1.60451i & x_3 = 0.65897-1.60451i \end{matrix} $$
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