Here's the question you clicked on:
math_proof
proof (1) Show that if n > 0 is a positive integer then the relation ≡n on integers defined by a ≡n b if n|(a − b) is an equivalence relation. (2) When n = 2, what are the equivalence classes? Can you see the connection with question 1? (3) What are the equivalence classes when n = 3? (4) Foragiven n>1,suppose that a ≡n b and c ≡n d. Prove that a+c ≡n b+d and ac ≡n bd.
i got the first one, but im confused about the rest