Answer the following questions about functions. 

A series of points in the form (x,y) is a function if every -value is different.

A graph is a function if a vertical line passes through the graph at most  time. 

1. What does it mean for a series of points to be a function?

- It means that for every x-value, there is a unique y-value associated with it. In other words, each x-value has only one corresponding y-value.

2. How can you determine if a graph is a function?
- You can determine if a graph is a function by using the vertical line test. If a vertical line passes through the graph at most one time at any point, then the graph represents a function. If the vertical line intersects the graph at more than one point, then the graph does not represent a function.