Answer :
Find all the number in the set that are less than -7.
The 'bigger' the negative number seems, the smaller it is.
So -15, -10.5, and -7.2 are all less than -7.
The 'bigger' the negative number seems, the smaller it is.
So -15, -10.5, and -7.2 are all less than -7.
-15<-10.5<-7.2<-7(<0)
x∈{-15, -10.5, -7.2}. These are less than -7
Answer: B, C, D