The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -2.1621\\[1 em]x_2 &= 0.5811+1.4053i\\[1 em]x_3 &= 0.5811-1.4053i \end{aligned} $$Polynomial $ -5x^3-5x^2+x-25 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.