The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.1278\\[1 em]x_2 &= 0.1361+1.2437i\\[1 em]x_3 &= 0.1361-1.2437i \end{aligned} $$Polynomial $ -5x^3+2x^2-8x+1 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.