ĐKXĐ : \(x\ge0\)
Ta có : \(x-2\sqrt{x}-1=0\)
=> \(x-2\sqrt{x}+1-2=0\)
=> \(\left(\sqrt{x}-1\right)^2=2\)
=> \(\left[{}\begin{matrix}\sqrt{x}-1=\sqrt{2}\\\sqrt{x}-1=-\sqrt{2}\end{matrix}\right.\)
=> \(\left[{}\begin{matrix}\sqrt{x}=1+\sqrt{2}\\\sqrt{x}=1-\sqrt{2}\left(L\right)\end{matrix}\right.\)
=> \(x=\left(1+\sqrt{2}\right)^2=3+2\sqrt{2}\) ( TM )
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