The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.0523\\[1 em]x_2 &= -1.2809+0.0702i\\[1 em]x_3 &= -1.2809-0.0702i\\[1 em]x_4 &= 0.4214+1.3263i\\[1 em]x_5 &= 0.4214-1.3263i \end{aligned} $$Polynomial $ 6x^5+10x^4+8x^3+21x^2+18x-1 $ has no rational roots that can be found using Rational Root Test, so the roots were found using Newton method.