Just take it one step at a time.

We must first show tha a~a.

so is (a, b) ~ (a, b)?

That is, ab = ba? If you are doing multiplication (which I assume), then yes, that statement is true.

Now let's assume a ~ b. Show that b ~ a.

Since a ~ b, ad = bc. So cb = da, and thus, b ~ a.

Now you try transitivity. Assume that a ~ b and b ~ c. Try to show that a ~ c.