Có ai bt cáh làm hông chỉ tui zới

`(7-sqrt{7})/(sqrt{7}-1)-6sqrt{1/3}-sqrt{10-2sqrt{21}}`

`=` `(sqrt{7}(sqrt{7}-1))/(sqrt{7}-1)-sqrt{(6^2.1)/3}-sqrt{7-2.sqrt{7.3}+3}`

`=` `sqrt{7}-sqrt{12}-sqrt{(sqrt{7}-sqrt{3})^2}`

`=` `sqrt{7}-sqrt{4.3}-|sqrt{7}-sqrt{3}|`

`=` `sqrt{7}-2sqrt{3}-(sqrt{7}-sqrt{3})`

`=` `sqrt{7}-2sqrt{3}-sqrt{7}+sqrt{3}`

`=` `-sqrt{3}`