Question

Help me answer this question Tutor's Note: First picture is the question, and picture 2 and 3 are the tutor's answers I sent to the student once the answer page was not working.

Answer 1

To know from a graph if it is a function or not we just need to look if the relation between the x-values and the y-values.

To be a function for each x-value there is just one y-value. If for a x-value there is two or more values of y, it is not a function. So let's look at our graphs:

As we can see above for the first three graphs, all are not functions once there are a least on or more x-values with more than one corresponding y-value. Let's look over the next three graphs:

As we can see above, graph 4, 5 and 6 represent a function once for all x-values, there are only one y-value.

NOTE: - For graph 5 We can see there are empty circles what means it is an open interval, so that points does not count.

- The x-values I mentioned are only the x-values for the functions.