The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 3.7588\\[1 em]x_2 &= -0.2128+0.4699i\\[1 em]x_3 &= -0.2128-0.4699i \end{aligned} $$Polynomial $ -3x^3+10x^2+4x+3 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.