The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 11.3578+10.5357i\\[1 em]x_2 &= 11.3578-10.5357i\\[1 em]x_3 &= -11.3578+10.5357i\\[1 em]x_4 &= -11.3578-10.5357i \end{aligned} $$Polynomial $ x^4-36x^2+57600 $ has no rational roots that can be found using Rational Root Test, so the roots were found using quartic formulas.