The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.6805\\[1 em]x_2 &= -0.5977\\[1 em]x_3 &= 4.9173 \end{aligned} $$Polynomial $ -x^3+5x^2-2 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.