The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 1.2513\\[1 em]x_2 &= -0.6256+5.7597i\\[1 em]x_3 &= -0.6256-5.7597i \end{aligned} $$Step 1:
Combine like terms:
$$ x^3 \color{blue}{-10} +32x \color{blue}{-32} = x^3+32x \color{blue}{-42} $$Step 2:
Polynomial $ x^3+32x-42 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.