(3x-1)^4-20(3x-1)^2=0

Question

(3x-1)^4-20(3x-1)^2=0

Answer 1

\begin{eqalign}
&$x = \frac{2 \sqrt{5} + 1}{3} \approx 1.824045318$\\
&$x=\frac{1}{3}\approx 0.333333333$\\
&$x=\frac{1-2\sqrt{5}}{3}\approx -1.157378652$
\end{eqalign}