tìm x: 3x + 43=115 3x+8=35 (3x + 2) . 25=192 13. (5x+4)=312 (9x+4):23=8 384:(5x-3)=12 156:(3x-2)=12 2x-7=1 7+5x=12 5-2x=3 làm nhanh nhé 60 điểm đấy

Đáp án+Giải thích các bước giải:

 `3x+43=115`

`=>3x=155-43`

`=>3x=72`

`=>x=72:3`

`=>x=24`

Vậy `x=24`

______________

`3x+8=35`

`=>3x=35-8`

`=>3x=27`

`=>x=27:3`

`=>x=9`

Vậy `x=9`

_____________

`(3x+2).25=192`

`=>3x+2=192:25`

`=>3x+2=7,68`

`=>3x=7,68-2`

`=>3x=5,68`

`=>x=5,68:3`

`=>x=\frac{142}{75}`

Vậy `x=\frac{142}{75}`

____________________

`13.(5x+4)=312`

`=>5x+4=312:13`

`=>5x+4=24`

`=>5x=20`

`=>x=20:5`

`=>x=4`

Vậy `x=4`

____________________

`(9x+4):23=8`

`=>9x+4=8.23`

`=>9x+4=184`

`=>9x=180`

`=>x=180:9`

`=>x=20`

Vậy `x=20`

________________

`384:(5x-3)=12`

`=>5x-3=384:12`

`=>5x-3=32`

`=>5x=35`

`=>x=35:5`

`=>x=7`

Vậy `x=7`

_____________

`156:(3x-2)=12`

`=>3x-2=156:12`

`=>3x-2=13`

`=>3x=15`

`=>x=15:3`

`=>x=5`

Vậy `x=5`

_____________

`2x-7=1`

`=>2x=8`

`=>x=4`

Vậy `x=4`

________

`7+5x=12`

`=>5x=12-7`

`=>5x=5`

`=>x=5:5`

`=>x=1`

Vậy `x=1`

____________

`5-2x=3`

`=>2x=5-3`

`=>2x=2`

`=>x=2:2`

`=>x=1`

Vậy `x=1`