The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -3.0689\\[1 em]x_2 &= 0.7844+0.4464i\\[1 em]x_3 &= 0.7844-0.4464i \end{aligned} $$Polynomial $ 2x^3+3x^2-8x+5 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.