The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.3566\\[1 em]x_2 &= -0.3566\\[1 em]x_3 &= -1.2541\\[1 em]x_4 &= 1.2541 \end{aligned} $$Polynomial $ 10x^4-17x^2+2 $ has no rational roots that can be found using Rational Root Test, so the roots were found using quartic formulas.