`a)` $\frac{5x+2}{6}$ `-` $\frac{8x-1}{3}$ `=` $\frac{4x+2}{5}$ `-` `5` `b)` $\frac{2x-8}{6}$ `-`$\frac{3x+1}{4}$ `=`$\frac{9x-2}{8}$ `+` $\frac{3x-1}{12}$ `c` `14``$\frac{1}{2}$ `-``$\frac{2(x+3)}{5}$ `=` `$\frac{3x}{2}$ `-` `$\frac{2(x-7)}{3}$

`a) (5x+2)/6 - (8x-1)/3 = (4x+2)/5 - 5`

`<=> [5(5x+2)]/30 - [10(8x-1)]/30 = [6(4x+2)]/30 - (30.5)/30`

`<=> (25x+10)/30 - (80x-10)/30 = (24x +12)/30 - 150/30`

`=> 25x + 10 - 80x +10 = 24x + 12 - 150`

`<=> 25x - 80x - 24x = -10 - 10 + 12 - 150`

`<=> -79x = -158`

`<=> x = 2` 

Vậy `S = {2}`

`b) (2x-8)/6 - (3x+1)/4 = (9x-2)/8 + (3x-1)/12`

`<=> [4(2x-8)]/24 - [6(3x+1)]/24 = [3(9x-2)]/24 + [2(3x-1)]/24`

`<=> (8x-32)/24 - (18x +6)/24 = (27x - 6)/24 + (6x -2)/24` 

`=> 8x - 32 - 18x - 6 = 27x - 6 + 6x - 2`

`<=> -10x - 38 = 33x -8`

`<=> -10x - 33x = 38- 8`

`<=> -43x = 30`

`<=> x = -30/43` 

Vậy `S = {-30/43}` 

 `c) 14 1/2 - [2(x+3)]/5 = (3x)/2 - [2(x-7)]/3`

`<=> 29/2 - (2x+6)/5 = (3x)/2 - (2x-14)/3`

`<=> (29.15)/30 - [6(2x+6)]/30 = (3x.15)/30 - [10(2x-14)]/30`

`<=> (435)/30 - (12x + 36)/30 = (45x)/30 - (20x -140)/30`

`=> 435 - 12x - 36 = 45x - 20x + 140`

`<=> -12x +399 = 25x + 140`

`<=> -12x -25x = -399 + 140`

`<=> -37x = -259`

`<=> x = 7` 

Vậy `S ={7}`