Đáp án:
`B=-5/(\sqrtx-1)`
Giải thích các bước giải:
`B=\sqrtx/(\sqrtx+1)-(\sqrtx+1)/(\sqrtx-1)-(2\sqrtx+4)/(x-1)`
`\to B=\sqrtx/(\sqrtx+1)-(\sqrtx+1)/(\sqrtx-1)-(2\sqrtx+4)/((\sqrtx+1)(\sqrtx-1))`
`\to B=(\sqrtx(\sqrtx-1)-(\sqrtx+1)(\sqrtx+1)-(2\sqrtx+4))/((\sqrtx+1)(\sqrtx-1))`
`\to B=(x-\sqrtx-(\sqrtx+1)^2-(2\sqrtx+4))/((\sqrtx+1)(\sqrtx-1))`
`\to B=(x-\sqrtx-(x+2\sqrtx+1)-(2\sqrtx+4))/((\sqrtx+1)(\sqrtx-1))`
`\to B=(x-\sqrtx-x-2\sqrtx-1-2\sqrtx-4)/((\sqrtx+1)(\sqrtx-1))`
`\to B=((x-x)+(-\sqrtx-2\sqrtx-2\sqrtx)+(-1-4))/((\sqrtx+1)(\sqrtx-1))`
`\to B=(-5\sqrtx-5)/((\sqrtx+1)(\sqrtx-1))`
`\to B=(-5(\sqrtx+1))/((\sqrtx+1)(\sqrtx-1))`
`\to B=-5/(\sqrtx-1)`
Vậy `B=-5/(\sqrtx-1)`
