The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -0.0602+0.9273i\\[1 em]x_2 &= -0.0602-0.9273i\\[1 em]x_3 &= 2.0602+0.6231i\\[1 em]x_4 &= 2.0602-0.6231i \end{aligned} $$Polynomial $ -x^4+4x^3-5x^2+3x-4 $ has no rational roots that can be found using Rational Root Test, so the roots were found using quartic formulas.