bài 2:tìm x a)1/4.(8/3-x)+1/5=3/4.(1/2-1) 2)5-1/2.(x-3)=6-1/5+1/2

Đáp án:

 `a)`

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

`=>1/4.(8/3-x)+1/5=3/4.(-1/2)`

`=>1/4.(8/3-x)+1/5=-3/8`

`=>1/4.(8/3-x)=-3/8-1/5`

`=>1/4.(8/3-x)=-23/40`

`=>8/3-x=(-23/40): 1/4`

 `=>8/3-x=-23/10`

`=>x=8/3+23/10`

`=>x=80/30+69/30`

`=>x=149/30`

Vậy `x=149/30`

`b)`

`5-1/2.(x-3)=6-1/5+1/2`

`=>5-1/2.(x-3)=60/10-2/10+5/10`

`=>5-1/2.(x-3)=63/10`

`=>1/2.(x-3)=5-63/10`

`=>1/2.(x-3)=-13/10`

`=>x-3=(-13/10): 1/2`

`=>x-3=-13/5`

`=>x=-13/5+3`

`=>x=2/5`

Vậy `x=2/5`