Answer:
The last one is a function.
Step-by-step explanation:
When the x value corresponds to different y values e.g. (1,2)(1,1), then it automatically isn't a function. Another simple way to find out if something is a function is to graph and try the vertical line test. If the line passes through multiple points on it's way down, then it's not a function.
Hope that helps!!!! :)
