Đáp án:+Giải thích các bước giải:
`A=((a+2\sqrta)/(\sqrta+2)-1):((a-\sqrta)/(\sqrta-1)+1)`
`=( (\sqrta(\sqrta+2))/(\sqrta+2)-1):( (\sqrta(\sqrta-1))/(\sqrta-1)+1)`
`=(\sqrta-1):(\sqrta+1)=(\sqrta-1)/(\sqrta+1)`
`B=(\sqrtx/(\sqrtx-1)-1/(x-\sqrtx)):(1/(\sqrtx+1)+2/(x-1))`
`=(\sqrtx/(\sqrtx-1)-1/(\sqrtx(\sqrtx-1))):(1/(\sqrtx+1)+2/((\sqrtx+1)(\sqrtx-1)))`
`=(x-1)/(\sqrtx(\sqrtx-1)):(\sqrtx-1+2)/((\sqrtx+1)(\sqrtx-1))`
`=((\sqrtx+1)(\sqrtx-1))/(\sqrtx(\sqrtx-1)):(\sqrtx+1)/((\sqrtx+1)(\sqrtx-1))`
`=(\sqrtx+1)/\sqrtx : 1/(\sqrtx-1) `
`=((\sqrtx+1)(\sqrtx-1))/\sqrtx = (x-1)/\sqrtx`
