The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -1.4329\\[1 em]x_2 &= -0.2836+2.0266i\\[1 em]x_3 &= -0.2836-2.0266i \end{aligned} $$Polynomial $ x^3+2x^2+5x+6 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.