The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.5081\\[1 em]x_2 &= -0.5081\\[1 em]x_3 &= 0.5081i\\[1 em]x_4 &= -0.5081i \end{aligned} $$Polynomial $ -30x^4+2 $ has no rational roots that can be found using Rational Root Test, so the roots were found using quartic formulas.