The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 4.8595\\[1 em]x_2 &= 1.0126+0.5235i\\[1 em]x_3 &= 1.0126-0.5235i\\[1 em]x_4 &= -0.4424+0.8687i\\[1 em]x_5 &= -0.4424-0.8687i \end{aligned} $$Polynomial $ x^5-6x^4+6x^3-3x^2+5x-6 $ has no rational roots that can be found using Rational Root Test, so the roots were found using Newton method.