3.|2.x+$\frac{1}{4}$ | -$\frac{1}{2}$ = $\frac{5}{2}$
3.|2.x+$\frac{1}{4}$ | = $\frac{5}{2}$ + $\frac{1}{2}$
3.|2.x+$\frac{1}{4}$ | = 3
|2.x+$\frac{1}{4}$ | = 3:3
|2.x+$\frac{1}{4}$ | = 1
TH1:
2.x+$\frac{1}{4}$ = 1
2.x =1-$\frac{1}{4}$
2.x = $\frac{3}{4}$
x =$\frac{3}{4}$:2
x = $\frac{3}{8}$
TH2:
2.x+$\frac{1}{4}$ = -1
2.x =-1 - $\frac{1}{4}$
2x = $\frac{-5}{4}$
x = $\frac{-5}{4}$ :2
x = $\frac{-5}{8}$
Vậy x ∈{ $\frac{-5}{8}$ ; $\frac{3}{2}$}
CHÚC BẠN HỌC TỐT!!!