$$-3-x+3x^2+6x^3+9x^4 = 0$$
Answer
$$ \begin{matrix}x_1 = 0.60339 & x_2 = -0.77234 & x_3 = -0.24886+0.80829i \\[1 em] x_4 = -0.24886-0.80829i & \\[1 em] \end{matrix} $$
Explanation
$$ \begin{aligned} -3-x+3x^2+6x^3+9x^4 &= 0&& \text{simplify left side} \\[1 em]9x^4+6x^3+3x^2-x-3 &= 0&& \\[1 em] \end{aligned} $$
This polynomial has no rational roots that can be found using Rational Root Test.
Roots were found using quartic formulas
This page was created using
Polynomial Equations Solver