`(2/3-0,25+2)-(2-5/2+1/4)-(2,5-1/3)`

`= 2/3 -1/4 +2-2+ 5/2 -1/4 -5/2 +1/3`

`= (2/3 +1/3) +(-1/4 -1/4) + (2-2) + (5/2-5/2)`

`= 3/3 + (-1/2) + 0 + 0`

`= 1 +(-1/2)`

`= 1/2`

`[4.(2.x-5)+12]:2=15`

`=> 4.(2.x-5)+12 =15*2`

`=> 4.(2.x-5)+12 =30`

`=> 4.(2.x-5)=30-12`

`=> 4.(2.x-5)= 18`

`=> 2.x-5=18/4`

`=> 2.x=19/2`

`=>x= 19/2 :2`

`=>x=19/4`

Ụa z hả bảo j vx nghèoo

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

`=> 3x-x=1/2+1/2`

`=> 2x= 2/4 + 2/4`

`=> 2x= 1`

`=>x=1/2`

__

`4- 7/2 x -1=5`

`=> 4- 7/2x -1-5=0`

`=> -7/2x-2=0`

`=> -7/2x=2`

`=>x=2:(-7/2)`

`=>x= -7/4`