Final answer:
The relation is not a function because the input '3' corresponds to multiple outputs (7, 8, and -2), violating the definition of a function.
Step-by-step explanation:
To determine whether a given relation is a function or not, one must check if every input (x-value) corresponds to exactly one output (y-value). In the relation provided, which is {(3,7),(3,8),(3,− 2), (4,5),(0,2)}, we can see that the input '3' is associated with three different outputs: 7, 8, and − 2.
Since a single input maps to multiple outputs, this violates the definition of a function, which states that each input should map to only one output. Therefore, the relation given is not a function