The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -1.5335\\[1 em]x_2 &= 0.5525+3.3536i\\[1 em]x_3 &= 0.5525-3.3536i \end{aligned} $$Polynomial $ 7x^3+3x^2+69x+124 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.