The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 335.3635\\[1 em]x_2 &= 627.4362\\[1 em]x_3 &= -832.7996 \end{aligned} $$Polynomial $ -x^3+130x^2+591400x-175237000 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.