The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.4679\\[1 em]x_2 &= 1.6527\\[1 em]x_3 &= 3.8794 \end{aligned} $$Polynomial $ x^3-6x^2+9x-3 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.