The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.9513+0.616i\\[1 em]x_2 &= 0.9513-0.616i\\[1 em]x_3 &= -0.9513+1.1961i\\[1 em]x_4 &= -0.9513-1.1961i \end{aligned} $$Polynomial $ x^4-2x+3 $ has no rational roots that can be found using Rational Root Test, so the roots were found using quartic formulas.