Is {(–2, 4), (5, 8), (3, 6), (5, 9)} a function? Algebra Expressions, Equations, and Functions Vertical Line Test 1 Answer Alan P. May 27, 2015 #{(-2,4), (5,8), (3,6), (5,9)}# is not a function since #f(5)# maps into 2 different values: #8 and 9# Answer link Related questions What is Vertical Line Test? What is an example of a graph that fails the vertical line test? How do you use the vertical line test? When is a relation a function? How do you determine if the following sets of points is a function: #{(2,3), (-1, 3), (4, 7), (-1, 5)}#? Why does the vertical line test work? Does a linear graph pass the vertical line test? Does a vertical line pass the vertical line test? What is the vertical and horizontal line tests for 1-1 function? Is {(8, –1), (–8, 1), (6, –1), (8, 6)} a function? See all questions in Vertical Line Test Impact of this question 598 views around the world You can reuse this answer Creative Commons License