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boyxuthanh


rút gọn
[tex]\sqrt{x - 2\sqrt{x-1}} - \sqrt{x-1}[/tex]
[tex]=\sqrt{(\sqrt{x-1})^2 - 2\sqrt{x - 1} +1} - /sqrt{x-1}[/tex]
[tex]=\sqrt{(\sqrt{x-1}-1)^2} - \sqrt{x -1}[/tex]
[tex]=\sqrt{x - 1} -1 -\sqrt{x-1} = -1[/tex]
[tex]\sqrt{x - 2\sqrt{x-1}} - \sqrt{x-1}[/tex]
[tex]=\sqrt{(\sqrt{x-1})^2 - 2\sqrt{x - 1} +1} - /sqrt{x-1}[/tex]
[tex]=\sqrt{(\sqrt{x-1}-1)^2} - \sqrt{x -1}[/tex]
[tex]=\sqrt{x - 1} -1 -\sqrt{x-1} = -1[/tex]
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