The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.5638\\[1 em]x_2 &= -0.6592\\[1 em]x_3 &= 1.3454 \end{aligned} $$Polynomial $ 4x^3-5x^2-2x+2 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.