`4x^2 - 4x + 1 = (5 - x)^2`
`<=> (2x - 1)^2 = (5 - x)^2`
`<=> |2x - 1| = |5 - x|`
`<=>` \(\left[ \begin{array}{l}2x - 1 = 5 - x\\2x - 1 = x - 5\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}3x = 6\\x = -4\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}x = 2\\x = -4\end{array} \right.\)