I need to know if these two graphs are a function, is one a function? is two a function?

                                     Question 7

The graph in question 7 is a function.

Step-by-step explanation:

In order to check whether the graph in question 7 is a function or not, we need to draw a vertical line anywhere on the graph, and if does not hit the graph more than once, it is a function.

It is observable that the vertical line will always intersect the graph in question 7 at the only place.

From the graph, it is clear the green vertical line intersects the graph at the only place. Hence, the graph in question 7 is a function.

Therefore, the graph in question 7 is a function.

                                               Question 8

The graph in question 8 is not a function.

Step-by-step explanation:

In order to check whether the graph in question 8 is a function or not, we need to draw a vertical line anywhere on the graph, and if does not hit the graph more than once, it is a function.

It is observable that the vertical line intersects the graph in question 8 at more than one place.

From the graph, it is clear the green vertical line intersects the graph at x=-3 at more than one place. We can not have the same x values for the two output values in order to be a function. Hence, the graph in question 8 would NOT be a function.

Therefore, the graph in question 8 is not a function.