The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 2.8473\\[1 em]x_2 &= -1.4237+0.2836i\\[1 em]x_3 &= -1.4237-0.2836i \end{aligned} $$Polynomial $ x^3-6x-6 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.