The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.6624\\[1 em]x_2 &= -1.4321\\[1 em]x_3 &= -4.4803 \end{aligned} $$Polynomial $ 4x^3+21x^2+10x-17 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.