The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -0.1774\\[1 em]x_2 &= -0.8467\\[1 em]x_3 &= 0.842\\[1 em]x_4 &= 1.582 \end{aligned} $$Polynomial $ 5x^4-7x^3-5x^2+5x+1 $ has no rational roots that can be found using Rational Root Test, so the roots were found using quartic formulas.