Final answer:
A set of points does not represent a function if an input value pairs with more than one output. In this case, the input 7 corresponds to two different outputs (5 and 3), thus the given set of points is not a function.
Step-by-step explanation:
To determine whether a set of points represents a function, we need to look at the input values (typically the x-values) and ensure that each input corresponds to exactly one output (the y-value). We are given the set of points (7,5), (9,7), (-2,9), (7,3), (1,1). By examining these points, we immediately see that the input value 7 is paired with two different outputs (5 and 3). This violates the definition of a function, which states that each input should be paired with exactly one output.
Therefore, the relationship described by the given set of points is not a function.