The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -465.701\\[1 em]x_2 &= 232.8505+403.3089i\\[1 em]x_3 &= 232.8505-403.3089i \end{aligned} $$Polynomial $ x^3+101000000 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.