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x ². ( 2x - 1 ) = 4. ( 2x -1 )
⇔ x ². ( 2x - 1 ) - 4. ( 2x -1 ) = 0
⇔ ( 2x - 1 ) . ( x ² - 4) = 0
⇔ ( 2x - 1 ) . ( x + 2 ) . ( x - 2 ) = 0
⇔\(\left[ \begin{array}{l}2x - 1 = 0\\x + 2 = 0\\ x - 2 = 0\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=\frac{1}{2} \\x=-2\\ x = 2\end{array} \right.\)
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