The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.2728\\[1 em]x_2 &= -0.573\\[1 em]x_3 &= 1.3079\\[1 em]x_4 &= -3.483\\[1 em]x_5 &= -1.2623+1.1026i\\[1 em]x_6 &= -1.2623-1.1026i \end{aligned} $$Polynomial $ -x^6-5x^5-5x^4+5x^3+15x^2+3x-2 $ has no rational roots that can be found using Rational Root Test, so the roots were found using Newton method.