The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.746\\[1 em]x_2 &= -1.123+0.6438i\\[1 em]x_3 &= -1.123-0.6438i \end{aligned} $$Polynomial $ 4x^3+6x^2-5 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.