$$3x^4+6x^3+17x^2+6x+18 = 0$$
Answer
$$ \begin{matrix}x_1 = 0.07735+1.12337i & x_2 = 0.07735-1.12337i & x_3 = -1.07735+1.88981i \\[1 em] x_4 = -1.07735-1.88981i & \\[1 em] \end{matrix} $$
Explanation
This polynomial has no rational roots that can be found using Rational Root Test.
Roots were found using quartic formulas
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