Đáp án + Giải thích các bước giải:
`a)`
`(2sqrt18-3sqrt7+5sqrt63).sqrt112`
`=2sqrt18.sqrt112-3sqrt7.sqrt112+5sqrt63.sqrt112`
`=2sqrt18.112 – 3sqrt7.112 + 5sqrt63.112`
`=2sqrt12.12.14 – 3sqrt28.28 + 5sqrt84.84`
`=24sqrt14-84+420`
`=336+24sqrt14`
`b)`
`(1sqrt48 - 6sqrt27 + sqrt12) : (2sqrt3)`
`=(1sqrt16.3 - 6sqrt9.3 + sqrt4.3 ): (2sqrt3)`
`=(4sqrt3-18sqrt3+2sqrt3) : (2sqrt3)`
`= (-12sqrt3) : (2sqrt3) = -6`