The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -2.1447\\[1 em]x_2 &= -0.4276+0.9914i\\[1 em]x_3 &= -0.4276-0.9914i \end{aligned} $$Polynomial $ 4x^3+12x^2+12x+10 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.