Đáp án+Giải thích các bước giải:
`(2sqrt3+sqrt5).sqrt3-sqrt60`
`=2.3+sqrt15-sqrt{4.15}`
`=6+sqrt15-2sqrt15`
`=6-sqrt15`
`(sqrt99-sqrt18-sqrt11).sqrt11+3sqrt22`
`=(3sqrt11-sqrt11-3sqrt2).sqrt11+3sqrt22`
`=(2sqrt11-3sqrt2).sqrt11+3sqrt22`
`=2.11-3sqrt22+3sqrt22`
`=22`
`sqrt{4x-4}+sqrt{9x-9}-sqrt{25x-25}(x>=1)`
`=sqrt{4(x-1)}+sqrt{9(x-1)}-sqrt{25(x-1)}`
`=2sqrt{x-1}+3sqrt{x-1}-5sqrt{x-1}`
`=0`