Identify the mapping diagram that represents the relation and determine whether the relation is a function.

{(-7, -5), (-4, 3), (-7, 2), (8, 4)}

The mapping diagram for the relation would be as follows:

-7 -> -5, 2
-4 -> 3
8 -> 4

In this diagram, each input of the relation is mapped to its corresponding output.

To determine if the relation is a function, we need to check if each input has only one output. Looking at the mapping diagram, it can be seen that the input -7 is associated with two different outputs: -5 and 2.

Therefore, the relation is not a function.