The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -2.9732\\[1 em]x_2 &= -0.0134+0.6483i\\[1 em]x_3 &= -0.0134-0.6483i \end{aligned} $$Polynomial $ 4x^3+12x^2+2x+5 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.