The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -3.4725\\[1 em]x_2 &= -0.5138+0.4099i\\[1 em]x_3 &= -0.5138-0.4099i \end{aligned} $$Polynomial $ 2x^3+9x^2+8x+3 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.