The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 1.8243\\[1 em]x_2 &= 3.9526\\[1 em]x_3 &= -0.3885+0.3556i\\[1 em]x_4 &= -0.3885-0.3556i \end{aligned} $$Polynomial $ x^4-5x^3+3x^2+4x+2 $ has no rational roots that can be found using Rational Root Test, so the roots were found using quartic formulas.