Question

Does the following table represent a function. If it does not represent a function, what is the minimum number of columns that could be removed to make it represent a function?

Answer 1

Answer: Choice A) Currently not a function. Remove one column (either of the columns that have x = 2) to make a function possible.

A function is not possible if we have some x input lead to multiple y outputs. This happens when x = 2. We have x = 2 pair up with y = 4 and y = 2 at the same time. Remove one of these columns to make this be a function.

The columns x = 1 and x = 3 repeat themselves with the same identical y value, so effectively we can remove these as well just to make thing simpler. But their presence means we can still have a function.