giúp mình với (15-x)+(x-12)=7-(-5+x) 5x-(x+1)=2x+5 (2 mũ x -4)-5=-1

`(15 -x) + (x-12) = 7 -(-5 +x)`

`=> 15 - x + x - 12 = 7 + 5 - x`

`=> (15 -12) + (x-x) = 12 -x`

`=> 3 + 0 = 12 -x`

`=> x = 12-3`

`=> x = 9`

Vậy `x=9`

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

`=> 5x - x - 1 = 2x + 5`

`=> 4x - 1 = 2x + 5`

`=> 4x - 2x = 5 +1`

`=> 2x = 6`

`=> x = 6:2`

`=>x=3`

Vậy `x=3`

`(2^x -4) - 5=-1`

`=> 2^x - 4 = -1 + 5`

`=> 2^x - 4 = 4`

`=> 2^x = 4 +4`

`=> 2^x = 8`

`=> 2^x = 2^3`

`=>x=3`

Vậy `x=3`

`#HPHG`