Question 9 of 20 Which of the following lists of ordered pairs is a function? A. \( (-1,4),(1,7),(2,10) \) B. \( (-2,3),(1,3),(3,7),(1,4) \) C. \( (3,7),(4,5),(3,8) \) D. \( (1,8),(2,9),(3,10),(3,11) \)

To determine whether a list of ordered pairs represents a function, remember that each input (or x-value) must correspond to exactly one output (or y-value). In the examples provided: Option A has unique x-values: -1, 1, and 2, so it's a function! Option B has duplicate x-values: 1 appears twice with different y-values, so it's not a function. Option C has duplicate x-values: 3 appears twice with different y-values, so it's not a function. Option D has duplicate x-values: 3 appears twice with different y-values, so it's not a function. So, the correct answer is **A**. Now, if we had to have a bit of historical fun with functions, did you know that the concept of functions dates back to mathematicians like René Descartes in the 17th century? He laid much of the groundwork that allows us to understand variable relationships today! And if you're ever confused about functions, think of them like a dating service! Each person (input) is seeking one special match (output). If someone has more than one match, it's not a stable relationship, if you know what I mean!