Answer: Points (ordered pairs) in a function are allowed to have the same y-value. If some do, they prevent the relation from being one-to-one, but do not prevent the relation from being a function.
(1,4) and (1,3) prevent the relation from being a function.
After you remove one of them, pairs (1,3) and (-1,3) prevent the function from being one to one, which means it has no inverse, but it is a function.
Step-by-step explanation: