$$x^3+x^5x+7x+2 = 0$$
Answer
$$ \begin{matrix}x_1 = -0.28256 & x_2 = -1.51473 & x_3 = -0.31692+1.36519i \\[1 em] x_4 = -0.31692-1.36519i & x_5 = 1.21556+0.94944i & x_6 = 1.21556-0.94944i \end{matrix} $$
Explanation
$$ \begin{aligned} x^3+x^5x+7x+2 &= 0&& \text{simplify left side} \\[1 em]x^3+x^6+7x+2 &= 0&& \\[1 em]x^6+x^3+7x+2 &= 0&& \\[1 em] \end{aligned} $$
This polynomial has no rational roots that can be found using Rational Root Test.
Roots were found using Newton method.
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