**We have **A = {5, 6}, B = {4, 5, 6} and C = {5, 6, 7}

Now, A X A = {(5, 5), (5, 6), (6, 5), (6, 6)}

B X B = {(4, 4), (4, 5), (4, 6), (5, 4), (5, 5), (5, 6), (6, 4), (6, 5), (6, 6)}

And C X C = {(5, 5), (5, 6), (5, 7), (6, 5), (6, 6), (6, 7), (7, 5), (7, 6), (7, 7)}

Now, (B X B) ∩ (C X C) = {(5, 5), (5, 6), (6, 5), (6, 6)}

**= A X A**

**Hence Proved**