The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.3788\\[1 em]x_2 &= -1.6894+1.5575i\\[1 em]x_3 &= -1.6894-1.5575i \end{aligned} $$Polynomial $ -x^3-3x^2-4x+2 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.