Đáp án:
$\\$
`A = [ (-35 + 49) ÷ 27 - (-149 + 25) ÷ 27)] ÷[327 × 712 - 327 × 512]`
`↔ A =[14 ÷ 27 - (-124) ÷ 27] ÷ [327 × (712 - 512)]`
`↔ A = [14 × 1/27 + 124 × 1/27] ÷ [327 × 200]`
`↔ A = [1/27 × (14 + 124)] ÷ 65400`
`↔ A = [1/27 × 138] ÷ 65400`
`↔ A = 49/6 ÷ 65400`
`↔ A = 49/6 × 1/65400`
`↔A=23/294300`
Vậy `A = 23/294300`