Okay...I hate abstracting but I will try my best...again.
So A U B = {1, 2, 3, 4, 5, 6, 7, 8} and C U D = {9, 10, 11, a, b, c, d, e}.
First attempt: h(x) = f(x) if x is element 1, 2, 3 OR g(x) if x is element 4, 5, 6, 7, 8. This is one-to-one because every element of A U B is mapped to...