$$x^5+0x^4+6x^3+5x^2+8x+20 = 0$$
Answer
$$ \begin{matrix}x_1 = -1.32827 & x_2 = 0.66413+1.82297i & x_3 = 0.66413-1.82297i \\[1 em] x_4 = 2i & x_5 = -2i \\[1 em] \end{matrix} $$
Explanation
This polynomial has no rational roots that can be found using Rational Root Test.
Roots were found using Newton method.
This page was created using
Polynomial Equations Solver