1,x.(x+7)=0
2,-(15-x)-(x-12)=7-(-5+x)
3,x.(x+7)=0
4,(x+12).(x-13)=0
5,(-x+5).(3-x)=0
6,(x-5).(x-11)=0
7,x.(2+x).(7-x)=0
8,(x mũ 2 + 11).(x mũ 2 -16)=0
9,(x mũ 2 -4).(x mũ 2 -4).(x mũ 2 -9)=0
10,(x-1).(x+2).(-x-3)=0
11,5-|x+1|=29
12, |x|<-5
13, 12< hoặc= |x|<15
14, -15<hoặc= x<17
15, 9<hoặc= |X-3|<11
16, 1986<|x+2|<2012(với x lớn nhất)
17, (x-2).(x-3)<0