Answer:
1. Yes 2. No 3. Yes 4. No
Step-by-step explanation: 1 is a function because none of the x values repeat, 2 isn't a function because in the x coordinates, -2 repeats, 3 is a function because if you were to draw a (vertical) line through each point, none of them have two points on one line, 4 is a function because none of the x coordinates point to more than one y coordinate