`#C_{J  u  l  y} `

`2. `

`a)(-1)/10+2/5x+7/20=1/10 `

`=>(-1)/10+2/5x=1/10-7/20 `

`=>(-1)/10+2/5x=-1/4 `

`=>2/5x=(-1/4)-(-1/10) `

`=>2/5x=-3/20 `

`=>x=-3/8 `

Vậy `x=-3/8 `

`b)1/3+1/2:x=-1/5 `

`=>1/2:x=(-1/5)-1/3 `

`=>1/2:x=-8/15 `

`=>x=1/2:(-8/15) `

`=>x=-15/16 `

Vậy `x=-15/16 `

`c)-2/3:x+5/8=-7/12 `

`=>-2/3:x=(-7/12)-5/8 `

`=>-2/3:x=-29/24 `

`=>x=(-2/3):(-29/24) `

`=>x=16/29 `

Vậy `x=16/29 `

`d)1/2x+2  1/2=3   1/2x-3/4 `

`=>1/2x+5/2=7/2x-3/4 `

`=>1/2x-7/2x=-5/2-3/4 `

`=>-3x=-13/4 `

`=>x=13/12 `

Vậy `x=13/12 `

`e)2/3x-2/5=1/2x-1/3 `

`=>2/3x-1/2x=2/5-1/3 `

`=>1/6x=1/15 `

`=>x=2/5 `

Vậy `x=2/5 `

`f)1/3x+2/5(x+1)=0 `

`=>1/3x+2/5x+2/5=0 `

`=>11/15x+2/5=0 `

`=>11/15x=-2/5 `

`=>x=-6/11 `

Vậy `x=-6/11 `