The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.4534+0.8969i\\[1 em]x_2 &= 0.4534-0.8969i\\[1 em]x_3 &= -0.8284+0.2372i\\[1 em]x_4 &= -0.8284-0.2372i \end{aligned} $$Polynomial $ 4x^4+3x^3+x^2+4x+3 $ has no rational roots that can be found using Rational Root Test, so the roots were found using quartic formulas.