The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.222\\[1 em]x_2 &= -0.6098\\[1 em]x_3 &= 7.3878 \end{aligned} $$Polynomial $ x^3-7x^2-3x+1 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.