The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -0.5085\\[1 em]x_2 &= -1.2436\\[1 em]x_3 &= 1.5185\\[1 em]x_4 &= 0.1168+1.4385i\\[1 em]x_5 &= 0.1168-1.4385i \end{aligned} $$Polynomial $ x^5-4x-2 $ has no rational roots that can be found using Rational Root Test, so the roots were found using Newton method.