rút gọn x - căn x \ x- 1 x-4 \ x- 4 căn x + 4 x căn y - y căn x \ x-y

Đáp án+Giải thích các bước giải:

`\frac{x-\sqrt{x}}{x-1}(x\ne1;x≥0)`

`=\frac{\sqrt{x}(\sqrt{x}-1)}{(\sqrt{x}-1)(\sqrt{x}+1)}`

`=\frac{\sqrt{x}}{\sqrt{x}+1}`

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`\frac{x-4}{x-4\sqrt{x}+4}(x\ne4;x≥0)`

`=\frac{(\sqrt{x}-2)(\sqrt{x}+2)}{(\sqrt{x}-2)^2}`

`=\frac{\sqrt{x}+2}{\sqrt{x}-2}`

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`\frac{x\sqrt{y}-y\sqrt{x}}{x-y}(x,y≥0;x\ney)`

`=\frac{\sqrt{xy}(\sqrt{x}-\sqrt{y})}{(\sqrt{x}+\sqrt{y})(\sqrt{x}-\sqrt{y})}`

`=\frac{\sqrt{xy}}{\sqrt{x}+\sqrt{y}}`