\(\sqrt{4x^2-4x+1}=x-1\\ \Leftrightarrow\sqrt{\left(2x\right)^2-2.2x+1}=x+1\\ \Leftrightarrow\sqrt{\left(2x-1\right)^2}=x-1\\ \Leftrightarrow\left|2x-1\right|=x-1\Leftrightarrow\left[{}\begin{matrix}2x-1=x-1\\2x-1=1-x\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{2}{3}\end{matrix}\right.\)
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