The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 2.738\\[1 em]x_2 &= -4.369+8.2363i\\[1 em]x_3 &= -4.369-8.2363i \end{aligned} $$Polynomial $ x^3+6x^2+63x-238 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.