The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 2.8428\\[1 em]x_2 &= -0.0464+0.5115i\\[1 em]x_3 &= -0.0464-0.5115i \end{aligned} $$Polynomial $ 8x^3-22x^2-6 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.