The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -0.2813\\[1 em]x_2 &= -1.316\\[1 em]x_3 &= -5.4027 \end{aligned} $$Polynomial $ x^3+7x^2+9x+2 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.