The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -0.793\\[1 em]x_2 &= 0.1649+0.6193i\\[1 em]x_3 &= 0.1649-0.6193i\\[1 em]x_4 &= -0.28+0.7454i\\[1 em]x_5 &= -0.28-0.7454i\\[1 em]x_6 &= 1.7616+0.3544i\\[1 em]x_7 &= 1.7616-0.3544i \end{aligned} $$Polynomial $ 6x^7-15x^6+4x^5+2x^4+7x^3+9x^2+x+4 $ has no rational roots that can be found using Rational Root Test, so the roots were found using Newton method.