The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.1987\\[1 em]x_2 &= -1.2865\\[1 em]x_3 &= -3.9122 \end{aligned} $$Polynomial $ x^3+5x^2+4x-1 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.