Question

{x:y is a natural number ,x<5 andx>7}​

Answer 1

Solution:- Empty

Empty set (ϕ): which has no elements

Natural numbers =1,2,3,4,...........

Natural numbers less than 5, (x<5)=1,2,3,4

Natural numbers greater than 7, (x>7)=8,9,10,.........

∵ A number can not be simultaneously less than 5 and greater than 7.

Hence, the set of natural numbers less than 5 and greater than 7 is empty.