`ĐKXĐ: x>0; x\ne1`
`B=((x-\sqrt{x})/(\sqrt{x}-1)-(\sqrt{x}+1)/(x+\sqrt{x})):(\sqrt{x}+1)/\sqrt{x}`
`B=[(\sqrt{x}(\sqrt{x}-1))/(\sqrt{x}-1)-(\sqrt{x}+1)/(\sqrt{x}(\sqrt{x}+1))].\sqrt{x}/(\sqrt{x}+1)`
`B=(\sqrt{x}-1/\sqrt{x}).\sqrt{x}/(\sqrt{x}+1)`
`B=(\sqrt{x}.\sqrt{x}-1)/\sqrt{x}.\sqrt{x}/(\sqrt{x}+1)`
`B=(x-1)/\sqrt{x}.\sqrt{x}/(\sqrt{x}+1)`
`B=((\sqrt{x}+1)(\sqrt{x}-1))/\sqrt{x}.\sqrt{x}/(\sqrt{x}+1)`
`B=\sqrt{x}-1`
Vậy với `x>0; x\ne1` thì `B=\sqrt{x}-1`
