Question

The Venn diagram shows all of the elements in sets A, B and ξ. Find the elements in (A ∩ B) U (A U B)’

Answer 1

This is impossible to answer without knowing what the sets A and B contain (and what ξ even refers to - universal set?).

However, we have

(A U B)' = A' ∩ B'

so that

(A ∩ B) U (A U B)' = (A ∩ B) U (A' ∩ B') = (A U A') ∩ (B U B')

If ξ is indeed the universal set, then both A U A' = ξ and B U B' = ξ, so we end up with ξ ∩ ξ = ξ.