Final answer:
Upon inspection of the relation, it is clear that it does not represent a function because the input 5 is associated with two different outputs. This violates the definition of a function, which requires each input to have exactly one output.
Step-by-step explanation:
To determine if the given relation represents a function, we assess if each input (x-value) is associated with exactly one output (y-value). The provided relation is: {(5,2),(-8,2),(9,10),(5,16)}. By inspection, the input 5 is associated with two different outputs: 2 and 16. Since a function must have only one output for each distinct input, this relation does not represent a function. The definition of a function is violated here because the x-value of 5 maps to more than one y-value.