Which of the following sets of ordered pairs is not a function

((-1, 2), (1, 3), (1, 5), (-3, 4))

Step-by-step explanation:

For a set of ordered pairs to be considered a function, a domain value should have exactly just 1 range value.

If a domain value is having more than 1 range value assigned to it, it is not a function. In order words, an x variable value should have exactly just one y variable value assigned to it.

x variables are domain values while y variables are the range values.

In the ordered pairs, ((-1, 2), (1, 3), (1, 5), (-3, 4)), the two pairs, (1, 3), (1, 5), have the same x variable value with different y-variable values assigned to each. This renders the set of ordered pairs not to be a function. Domain value 1, is having different range value of 3 and 5.