$$0 = 1-2x-4x^3$$
Answer
$$ \begin{matrix}x_1 = 0.38546 & x_2 = -0.19273+0.78194i & x_3 = -0.19273-0.78194i \end{matrix} $$
Explanation
$$ \begin{aligned} 0 &= 1-2x-4x^3&& \text{simplify right side} \\[1 em]0 &= -4x^3-2x+1&& \text{move all terms to the left hand side } \\[1 em]0+4x^3+2x-1 &= 0&& \text{simplify left side} \\[1 em]4x^3+2x-1 &= 0&& \\[1 em] \end{aligned} $$
This polynomial has no rational roots that can be found using Rational Root Test.
Roots were found using qubic formulas.
This page was created using
Polynomial Equations Solver