The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -0.3454\\[1 em]x_2 &= 2.7023\\[1 em]x_3 &= -2.8569 \end{aligned} $$Polynomial $ 12x^3+6x^2-92x-32 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.