The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -1.6823\\[1 em]x_2 &= -0.6588+1.1615i\\[1 em]x_3 &= -0.6588-1.1615i \end{aligned} $$Polynomial $ x^3+3x^2+4x+3 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.