The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.3653\\[1 em]x_2 &= -1.9199\\[1 em]x_3 &= 8.5546 \end{aligned} $$Polynomial $ x^3-7x^2-14x+6 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.