The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -0.8607\\[1 em]x_2 &= 0.0794+0.5594i\\[1 em]x_3 &= 0.0794-0.5594i\\[1 em]x_4 &= -0.4165+0.9502i\\[1 em]x_5 &= -0.4165-0.9502i\\[1 em]x_6 &= 0.9341+0.9045i\\[1 em]x_7 &= 0.9341-0.9045i \end{aligned} $$Polynomial $ 6x^7-2x^6+4x^5+2x^4+8x^3+9x^2+x+3 $ has no rational roots that can be found using Rational Root Test, so the roots were found using Newton method.