The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 4.5251\\[1 em]x_2 &= 0.7375+0.8844i\\[1 em]x_3 &= 0.7375-0.8844i \end{aligned} $$Polynomial $ x^3-6x^2+8x-6 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.