The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -0.4076\\[1 em]x_2 &= 0.4492\\[1 em]x_3 &= 0.2143+0.4001i\\[1 em]x_4 &= 0.2143-0.4001i\\[1 em]x_5 &= -0.2376+0.3594i\\[1 em]x_6 &= -0.2376-0.3594i\\[1 em]x_7 &= -1.7475+22.2918i\\[1 em]x_8 &= -1.7475-22.2918i \end{aligned} $$Polynomial $ 2x^8+7x^7+1000x^6+5x^5+3x^4+2x^3+3x^2-5x-7 $ has no rational roots that can be found using Rational Root Test, so the roots were found using Newton method.