The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 0.0522\\[1 em]x_2 &= -0.5033+0.9091i\\[1 em]x_3 &= -0.5033-0.9091i\\[1 em]x_4 &= -0.3562+1.6831i\\[1 em]x_5 &= -0.3562-1.6831i \end{aligned} $$Polynomial $ 6x^5+10x^4+28x^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.