$$-x^3+3x^2+26x+20 = 0$$
Answer
$$ \begin{matrix}x_1 = -0.88679 & x_2 = -3.18788 & x_3 = 7.07467 \end{matrix} $$
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