Two sets are called disjoint if and only if these two set have no common element i.e A∩B=∅

[i=imaginory root of unity which is a complex no.]

since the solution of x doesnot belongs to real no hence the set is null set

A ⊆B means Set A is contained in the set B.So common region is The Set A

A ⊆B refers to A set is contained in the Set B.So Set B is bigger.So union the sets will be B

LetA={1,2,3,4}andB={1,2,3,4,5,6}HereA∩B={1,2,3,4}NowA∪(A∩B)={1,2,3,4,}=A

LetA={1,2,3,4}andB={1,2,3,4,5,6}HereA∪B={1,2,3,4,5,6}NowA∩(A∪B)={1,2,3,4,}=A

Intelligency Can not measured by numbers i.e the collection is not well defined thats why it can not be called as a Set