The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -0.7732\\[1 em]x_2 &= 0.11+0.573i\\[1 em]x_3 &= 0.11-0.573i\\[1 em]x_4 &= -0.2391+0.7473i\\[1 em]x_5 &= -0.2391-0.7473i\\[1 em]x_6 &= 1.6823+0.5058i\\[1 em]x_7 &= 1.6823-0.5058i \end{aligned} $$Polynomial $ 6x^7-14x^6+4x^5+2x^4+7x^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.