The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= -0.1309\\[1 em]x_2 &= -2.1974\\[1 em]x_3 &= 0.1641+1.8573i\\[1 em]x_4 &= 0.1641-1.8573i \end{aligned} $$Polynomial $ x^4+2x^3+3x^2+8x+1 $ has no rational roots that can be found using Rational Root Test, so the roots were found using quartic formulas.