1、|x-500|＞5
x-500<-5或x-500>5
x<495或x>505
2、|2x+5|≤7
-7≤2x+5≤7
-6≤x≤1
3、|2x-5|＞3
2x-5<-3或2x-5>3
x<1或x>4
4、|7-5x|≤3
-3≤7-5x≤3
-10≤-5x≤-4
4/5≤x≤2
5、1≤|2x-1|＜2
1≤2x-1＜2或-2<2x-1≤-1
1≤x＜3/2或-1/2
x-500>5或x-500<-5,解得:x>505或x<495
-7<=2x+5<=7,解得:-6<=x<=1
2x-5>3或2x-5<-3,解得:x>4或x<1
变为:|5x-7|<=3,即-3<=5x-7<=3,解得:4/5<=x<=2
1<=2x-1<2或-2<2x-1<=-1,解得:1<=x<3/2或-1/2
X>505或x<495
|2x+5|≤7 -7≤ 2x+5≤7 -12≤ 2x≤2 -6≤ x≤1
|2x-5|＞3 2x-5＞3 或2x-5<-3 x＞4 或x<1
|7-5x|≤3 -3≤5x-7≤3 4≤5x≤10 4/5≤5x≤2
1≤|2x-1|＜2 -2＜2x-1＜2且（2x-1≤-1或1≤2x-1）
为-2＜2x-1≤-1或1≤2x-1＜2
-1/2＜x≤0或1≤x＜3/2就是(-1/2,0]u[1,3/2)
