The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 2.7693\\[1 em]x_2 &= 0.1154+0.5897i\\[1 em]x_3 &= 0.1154-0.5897i \end{aligned} $$Polynomial $ x^3-3x^2+x-1 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.