For any three sets A, B and C, (A – B) – (B – C) is equal to __________
Solution
\[ (A – B) – (B – C) \]
\[ = (A \cap B’) – (B \cap C’) \]
\[ = (A \cap B’) \cap (B \cap C’)’ \]
\[ = (A \cap B’) \cap (B’ \cup C) \]
\[ = (A \cap B’) \cup (A \cap B’ \cap C) \]
\[ = A \cap B’ \]
\[ = A – B \]
Answer
\[ \boxed{A – B} \]