Final answer:
The relation is not a function because the x-value 6 maps to two different y-values, which violates the definition of a function.
Step-by-step explanation:
The question is asking whether the relation {(4, 5), (6, -2), (-5, 0), (6, 1)} is a function. To determine this, we look at the x-values (which represent the input or the domain of the relation) and ensure that each x-value maps to exactly one y-value. In a function, every input must have a unique output. In the given set, the x-value 6 is associated with two different y-values, -2 and 1. This violates the definition of a function because the same input (6) does not have a unique output. Therefore, the relation is not a function.