Answer: 9.
- A 9
- B 6
- C 3
- D 27
Correct answer: A. 9
Explanation: n(A × A) = n(A) × n(A) = 3 × 3 = 9.
A Venn diagram makes set identities visual: A∪B is everything inside either circle, A∩B is only the overlap, and the region outside both circles represents the complement of their union - directly illustrating De Morgan's law (A∪B)′ = A′∩B′.
Concept context
Types of sets, operations (union/intersection/complement), relations, and types of functions with domain and range