The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -0.1982\\[1 em]x_2 &= 7.4838\\[1 em]x_3 &= 64.7144 \end{aligned} $$Polynomial $ -x^3+72x^2-470x-96 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.