7 và 1/2x +3(x-1)=9/2 4 và 3/2x - 3(2x+1)=7/3

`7 1/2 x + 3(x-1) = 9/2`

`15/2 x + 3(x-1) = 9/2`

`3(5/2x) + 3(x-1) = 9/2`

`3(5/2 x + x-1) = 9/2`

`5/2 x + x-1 = 9/2 : 3`

`5/2 x + x = 3/2 + 1`

`(5/2 + 1) x = 5/2`

`7/2 x = 5/2`

`x = 5/2 : 7/2`

`x = 5/7`

`__________`

`4 3/2 x - 3(2x+1) = 7/3`

`11/2 x - 3(2x+1) = 7/3`

`3(11/6 x) - 3(2x+1) = 7/3`

`3(11/6 x - 2x - 1) = 7/3`

`11/6 x - 2x - 1 = 7/3 : 3`

`11/6 x - 2x = 7/9 + 1`

`(11/6 - 2)x = 16/9`

`(-1)/6 x = 16/9`

`x = 16/9 : (-1)/6`

`x = (-32)/3`

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