This week in class we learned how to determine which relation is a function.
There were several ways of figuring this out.

In a arrow diagram, if one input has more than one arrow it is not a function.

In ordered pairs, if you have more than one ordered pair with the same input value, but different outputs it is not a function.

On graphs, you can check if it pass the vertical line test. If a vertical line crosses the graph more than once then it is not a function.

One output may correspond to multiple inputs and it will still be a function.

Input: independent variables and make up domain.
Output: dependent variables and make up range.