Đáp án:
`8,`
`2 (3/2 - x) -1/2 = 7x - 1/4`
`↔ 3 - 2x - 1/2 = 7x - 1/4`
`↔ -2x + (3 - 1/2) = 7x - 1/4`
`↔ -2x + 5/2 = 7x - 1/4`
`↔ -2x - 7x = -5/2 - 1/4`
`↔ -9x = (-11)/4`
`↔ x = (-11)/4 ÷ (-9)`
`↔ x = 11/36`
Vậy `x =11/36`
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`9,`
`1/5 ( (-3)/5 - 10) + 5x = x - 2/3`
`↔ 1/5 × (-53)/5 + 5x = x - 2/3`
`↔ 5x -53/25 = x - 2/3`
`↔ 5x - x = 53/25 - 2/3`
`↔ 4x = 109/75`
`↔ x = 109/75 ÷ 4`
`↔ x = 109/300`
Vậy `x = 109/300`
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`10,`
`(-3)/2 (5 - 1/2) + 4 = (x - 1/2) - 1`
`↔ (-3)/2 × 9/2 + 4 = (x - 1/2) - 1`
`↔ (-27)/4 + 4 = (x - 1/2) - 1`
`↔ x-1/2= (-11)/4`
`↔ x = (-11)/4 + 1/2`
`↔ x= (-9)/4`
Vậy `x=(-9)/4`
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`11,`
`1/3x - 2/3 = 1/2 (1/4 - 4)`
`↔ 1/3x - 2/3 = 1/2 × (-15)/4`
`↔ 1/3x - 2/3 = (-15)/8`
`↔ 1/3x = (-15)/8 + 2/3`
`↔ 1/3x = (-29)/24`
`↔ x = (-29)/24 ÷ 1/3`
`↔ x=(-29)/8`
Vậy `x=(-29)/9`
