Hi there,
The first one is a function this is because it has a straight line and you are able to figure out the slope.
The second one is not a function because it is not a straight line and with that you are unable to determine the slope.
The third one is a function. It has a straight line.
Lastly, the fourth one is not a function. It doesn't have a straight line
Hope these are correct :)
Have a great day
