The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -2.8972\\[1 em]x_2 &= -0.0514+1.0163i\\[1 em]x_3 &= -0.0514-1.0163i \end{aligned} $$Polynomial $ 3x^3+9x^2+4x+9 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.