The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 4.6976\\[1 em]x_2 &= -0.3488+1.075i\\[1 em]x_3 &= -0.3488-1.075i \end{aligned} $$Polynomial $ x^3-4x^2-2x-6 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.