How do I find equivalence classes? Let A = {a, b, c, d, e} Suppose R is an equivalence relation on A. Suppose R has three equivalence classes. Also aRd and bRc. Write out R as a set. From my understanding an equivalence relation is reflexive, symmetric & transitive. I understand that but what is it saying when aRd and bRc? How can I form equivalence classes from this information?

It means that $a$ and $d$ belong to the same equivalence class, and that $b$ and $c$ belong to the same equivalence class.

Now, use transivity, and the fact that there are **three** equivalence classes to sort things out; for instance, can $a$ and $b$ be in the same equivalence class? (i.e. would you still have three classes if this were true?)