Let a be a non-empty set and let s = p(a) be its power set. let b be a non-empty subset of a. on s, we define a relation r as r={a, a2) esx s]4,nb= a2 n b} show that r is an equivalence relation 2 marks describe the equivalence classes of r when a = z and b = {1,2,3} 2 marks