The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -19.5003\\[1 em]x_2 &= -0.2498+0.4404i\\[1 em]x_3 &= -0.2498-0.4404i \end{aligned} $$Polynomial $ x^3+20x^2+10x+5 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.