$$-x^3+2x^2+28x+23 = 0$$
Answer
$$ \begin{matrix}x_1 = -0.90679 & x_2 = -3.78841 & x_3 = 6.6952 \end{matrix} $$
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