help meeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

Đáp án:

`b)`

`|x-4|-\frac{1}{4}=\frac{7}{4}`

`=> |x-4|=\frac{7}{4}+\frac{1}{4}`

`=> |x-4|=\frac{8}{4}`

`=> |x-4|=2`

Ta xét `2TH:`

`+)TH1: x-4=2`

`=> x=2+4`

`=> x=6`

`+)TH2: x-4=-2`

`=> x=-2+4`

`=> x=2`

Vậy `x\in{6;2}`