The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -0.5069\\[1 em]x_2 &= -1.593\\[1 em]x_3 &= 16.0999 \end{aligned} $$Polynomial $ x^3-14x^2-33x-13 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.