Đáp án+Giải thích các bước giải:
`2)`
`(x+y-2\sqrt{xy})/(x\sqrty-y\sqrtx)`
`=(\sqrtx-\sqrty)^2/(\sqrt{xy}(\sqrtx-\sqrty))`
`=(\sqrtx-\sqrty)/(\sqrt{xy})`
`4)`
`(x-\sqrtx-2\sqrtx+2)/(x-1)`
`=(\sqrtx(\sqrtx-1)-2(\sqrtx-1))/((\sqrtx-1)(\sqrtx+1))`
`=((\sqrtx-1)(\sqrtx-2))/((\sqrtx-1)(\sqrtx+1))`
`=(\sqrtx-2)/(\sqrtx+1)`
`6)`
`(\sqrt{xy}-3\sqrty)/(x\sqrty-5\sqrt{xy}+6\sqrty)`
`=(\sqrty(\sqrtx-3))/(x\sqrty-2\sqrt{xy}-3\sqrt{xy}+6\sqrty)`
`=(\sqrty(\sqrtx-3))/(\sqrt{xy}(\sqrtx-2)-3\sqrty(\sqrtx-2))`
`=(\sqrty(\sqrtx-3))/((\sqrtx-2)(\sqrt{xy}-3\sqrty))`
`=(\sqrty(\sqrtx-3))/(\sqrty(\sqrtx-3)(\sqrtx-2))`
`=1/(\sqrtx-2)`
`8)`
`((x-\sqrtx)/(\sqrtx-1)+2)(2-(\sqrtx+x)/(1+\sqrtx))`
`=((\sqrtx(\sqrtx-1))/(\sqrtx-1)+2)(2-(\sqrtx(1+\sqrtx))/(1+\sqrtx))`
`=(\sqrtx+2)(2-\sqrtx)`
`=2^2-(\sqrtx)^2`
`=4-x`
`10)`
`(a\sqrta-b\sqrtb)/(\sqrta-\sqrtb)+\sqrt{ab}`
`=((\sqrta)^3-(\sqrtb)^3)/(\sqrta-\sqrtb)+\sqrt{ab}`
`=((\sqrta-\sqrtb)(a+\sqrt{ab}+b))/(\sqrta-\sqrtb)+\sqrt{ab}`
`=a+\sqrt{ab}+b+\sqrt{ab}`
`=a+2\sqrt{ab}+b`
`=(\sqrta+\sqrtb)^2`
