The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 1.4362\\[1 em]x_2 &= -2.0674\\[1 em]x_3 &= 0.3156+1.8078i\\[1 em]x_4 &= 0.3156-1.8078i \end{aligned} $$Polynomial $ x^4+4x-10 $ has no rational roots that can be found using Rational Root Test, so the roots were found using quartic formulas.