The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -0.6701\\[1 em]x_2 &= 7.3351+13.154i\\[1 em]x_3 &= 7.3351-13.154i \end{aligned} $$Polynomial $ x^3-14x^2+217x+152 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.