The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 1.4336\\[1 em]x_2 &= 0.3156+1.1868i\\[1 em]x_3 &= 0.3156-1.1868i\\[1 em]x_4 &= -1.0324+0.8856i\\[1 em]x_5 &= -1.0324-0.8856i \end{aligned} $$Polynomial $ x^5-x^2-4 $ has no rational roots that can be found using Rational Root Test, so the roots were found using Newton method.