The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.8831\\[1 em]x_2 &= -0.254+1.2783i\\[1 em]x_3 &= -0.254-1.2783i \end{aligned} $$Polynomial $ 8x^3-3x^2+10x-12 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.