Đáp án:
2.
`x : 142 = 625 - 457`
`x : 142 = 168`
`x = 168 × 142`
`x = 23856`
Vậy `x = 23856`
`x + 136 = 11 × 192`
`x + 136 = 2112`
`x = 2112 - 136`
`x = 1976`
Vậy `x = 1976`
3.
`624 : 3 - 324 : 3`
`= 624 : 3/1 - 324 : 3/1`
`= 624 × 1/3 - 324 × 1/3`
`= (624 - 324) × 1/3`
`= 300 × 1/3`
`= 100`
`(125 × 36) : (5 × 9)`
`= 4500 : 45`
`= 100`