The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 5.3495\\[1 em]x_2 &= -0.1747+1.356i\\[1 em]x_3 &= -0.1747-1.356i \end{aligned} $$Polynomial $ x^3-5x^2-10 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.