$$6^3+5x^2-2x-1 = 0$$
Answer
$$ \begin{matrix}x_1 = \dfrac{ 1 }{ 5 }+\dfrac{\sqrt{ 1074 }}{ 5 }i & x_2 = \dfrac{ 1 }{ 5 }-\dfrac{\sqrt{ 1074 }}{ 5 }i \\[1 em] \end{matrix} $$
Explanation
$$ \begin{aligned} 6^3+5x^2-2x-1 &= 0&& \text{simplify left side} \\[1 em]216+5x^2-2x-1 &= 0&& \\[1 em]5x^2-2x+215 &= 0&& \\[1 em] \end{aligned} $$
$ 5x^{2}-2x+215 = 0 $ is a quadratic equation.
You can use step-by-step quadratic equation solver to see a detailed explanation on how to solve this equation.
This page was created using
Polynomial Equations Solver