$$x^3-5x^2+2x+8 = 4$$
Answer
$$ \begin{matrix}x_1 = -0.68133 & x_2 = 1.35793 & x_3 = 4.3234 \end{matrix} $$
Explanation
$$ \begin{aligned} x^3-5x^2+2x+8 &= 4&& \text{move all terms to the left hand side } \\[1 em]x^3-5x^2+2x+8-4 &= 0&& \text{simplify left side} \\[1 em]x^3-5x^2+2x+4 &= 0&& \\[1 em] \end{aligned} $$
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