Đáp án:
`B=-11`
Giải thích các bước giải:
`B= {15}/{\sqrt{6}+1} + 4/{\sqrt{6}-2} - {12}/{3-\sqrt{6}}-\sqrt{6}`
`={15(\sqrt{6}-1)}/{(\sqrt{6}+1)(\sqrt{6}-1)}+{4(\sqrt{6}+2)}/{(\sqrt{6}-2)(\sqrt{6}+2)}-{12(3+\sqrt{6})}/{(3-\sqrt{6})(3+\sqrt{6})}-\sqrt{6}`
`={3.5(\sqrt{6}-1)}/{6-1^2}+{2.2(\sqrt{6}+2)}/{6-2^2}-{3.4(3+\sqrt{6})}/{3^2-6}-\sqrt{6}`
`=3(\sqrt{6}-1)+2(\sqrt{6}+2)-4(3+\sqrt{6})-\sqrt{6}`
`=3\sqrt{6}-3+2\sqrt{6}+4-12-4\sqrt{6}-\sqrt{6}`
`=(3+2-4-1).\sqrt{6}-3+4-12=-11`
Vậy `B=-11`
