3,|x+¼|

3,|x+¼|
3,|x+¼|

3,|x+¼|
|x+¼|≤½
-½≤x+¼≤½
-½-¼≤x≤½-¼
-3/4≤x≤¼
答案：-3/4≤x≤¼

-3/4<=1/4

①x+1/4<=1/2
x<=1/2-1/4=1/4
x<=1/4
②-（x+1/4）<=1/2
-x-1/4<=1/2
-x<=3/4
x>=-3/4
∴-3/4<=x<=1/4