The sets of ordered pairs that represent functions are:
1. {(1, 2), (2, 3), (3, 4), (3, 5), (5, 6)}:
This set is not a function because the input value 3 is associated with two different output values, 4 and 5.
2. {(1, 1), (2, 2), (3, 3), (4, 4), (5, 5)}:
This set is a function because each input value is associated with a unique output value. In other words, there are no repeated input values.
3. {(1, 1), (2, 1), (3, 1), (4, 1), (5, 1)}:
This set is a function because it represents a vertical line where each input value is associated with the same output value. While the output value is the same for all input values, it still fulfills the definition of a function.
4. {(1, 1), (1, 2), (1, 3), (1, 4), (1, 5)}:
This set is not a function because the input value 1 is associated with multiple output values, 1, 2, 3, 4, and 5.