Is this graph a function or not a function?

It is a function.

Step-by-step explanation:

You can test if a graph is a function if you draw a vertical line anywhere on the graph and you see it hits two points.

This is the table for the graph.

Remember these rules:

We can check these two rules for this graph:

Keep in mind that two different x-values can have the same y value.

Figure 1:

It has two x values with the same y-values.

Figure 2 and 3:

The vertical line goes through two points. So the same x-value has two different y-values.

-Chetan K