Suppose the graph of y = f(x) includes the points (1,5), (2,3) and (3,1).
Based only on this information, there are two points that must be on the graph of y = f(x(x)) . If we call those points (a,b) and (c,d) what is ab + cd?
There was a typo. I edited my answer and now it should be correct. However, if you understood my method and actually read the solution, not just the answer, you should have seen where I went wrong.
It's fine if you don't understand my solution- just ask.