this is just a case of applying definitions. Do you know what it means for a relation to be an equivalence relation? reflexive? symmetric? transitive?

Hint: A relation is said to be an "equivalence relation" if it is reflexive, symmetric and transitive.

Proving each of those cases are true for this relation should not be very difficult

Hint 2: A somewhat similar problem was done here. There are also definitions for all the terms mentioned in that thread as well. Use it as a guide