2. 3 is not a function
3. 4 is a function
To be a function it has to pass the vertical line test, meaning the x value can not repeat. So for this problem, you need to look at the ordered pair (x,y). For problem 2, answer 3 is not a function because the x value of 1 appears twice. For problem 3, answer 4 is a function because there aren't any x values being repeated.
