2 câu trả lời
`12` x `4+12` x `5+12`
`= 12` x `4+12` x `5+12` x `1`
`=12` x `(4+5+1)`
`=12` x `10`
`=120.`
`12` `×` `4` `+` `12` `×` `5` `+` `12`
`=` `12` `×` `(` `4` `+` `5` `)` `+` `12`
`=` `12` `×` `9` `+` `12`
`=` `108` `+` `12`
`=` `120`