Problem 13.2: equivalence relation (2 points) Let A=N+N+be the set of pairs of positive natural numbers. Let AA be a binary relation on A. The tuple ((a,b),(c,d)) is an element of if and only if ad=bc (the product of a and d is equal to the product of b and c ). Show that is an equivalence relation (i.e., is reflexive, symmetric and transitive). For each property, first state what you are trying to show before you provide the argument