Respuesta :

Answer:

4

Step-by-step explanation:

There can be no repeating x values

number 4 does not fit that criteria and therefore it is not a function

Answer:

Question #4 represents

Step-by-step explanation:

In question #4, a single x value (input) has two y-values (outputs).  This automatically disqualifies #4 as a function.  It's only a relationship.