The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 1.4423\\[1 em]x_2 &= -0.7211+1.249i\\[1 em]x_3 &= -0.7211-1.249i \end{aligned} $$Polynomial $ x^3-3 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.