`a)1/5+x=1/3`
`<=>x=1/3-1/5`
`<=>x=2/15`
Vậy `x=2/15`
`b)|(-1)/2-x|=1/3`
`=>(-1)/2-x=+-1/3`
`<=>[((-1)/2-x=1/3),((-1)/2-x=(-1)/3):}`
`<=>[(x=(-1)/2-1/3),(x=(-1)/2-(-1)/3):}`
`<=>[(x=(-5)/6),(x=(-1)/6):}`
Vậy `x=(-5)/6` hoặc `x=(-1)/6`
`c)1/4+3/4x=3/4`
`<=>3/4x=3/4-1/4`
`<=>3/4x=1/2`
`<=>x=1/2:3/4`
`<=>x=2/3`
Vậy `x=2/3`