Đáp án+Giải thích các bước giải:
`6)(sqrt(xy)-3sqrty)/(xsqrty-5sqrt(xy)+6sqrty)`
`=(sqrty(sqrtx-3))/(sqrty(x-5sqrtx+6))`
`=(sqrtx-3)/(x-2sqrtx-3sqrtx+6)`
`=(sqrtx-3)/(sqrtx(sqrtx-2)-3(sqrtx-2))`
`=(sqrtx-3)/((sqrtx-2)(sqrtx-3))`
`=1/(sqrtx-2)`
`9)(a+b+2sqrt(ab))/(sqrta+sqrtb)-(a-b)/(sqrta-sqrtb)`
`=(sqrta+sqrtb)^2/(sqrta+sqrtb)-((sqrta-sqrtb)(sqrta+sqrtb))/(sqrta-sqrtb)`
`=(sqrta+sqrtb)-(sqrta+sqrtb)`
`=0`
`10)(asqrta-bsqrtb)/(sqrta-sqrtb)+sqrt(ab)`
`=((sqrta-sqrtb)(a+sqrt(ab)+b))/(sqrta-sqrtb)+sqrt(ab)`
`=a+sqrt(ab)+b+sqrt(ab)`
`=a+2sqrt(ab)+b`
`11)((ysqrty-xsqrtx)/(sqrty-sqrtx)+sqrt(xy))((sqrty-sqrtx)/(y-x))^2`
`=(((sqrty-sqrtx)(x+sqrt(xy)+y))/(sqrty-sqrtx)+sqrt(xy))((sqrty-sqrtx)/((sqrty-sqrtx)(sqrty+sqrtx)))^2`
`=(x+sqrt(xy)+y+sqrt(xy))(1/(sqrty+sqrtx))^2`
`=(x+2sqrt(xy)+y)(1/(sqrty+sqrtx))^2`
`=(sqrtx+sqrty)^2(1/(sqrty+sqrtx))^2`
`=[(sqrtx+sqrty)(1/(sqrtx+sqrty))]^2`
`=1^2=1`
