Answer:
The input (domain) are usually on the left side of the circle.
Domain = [-2, 0, 3, 4, 6]
The output (range) are usually on the right side of the circle.
Range = [-3, -2, 0, 1, 2, 4]
Since the domain of 3 is pointing at two ranges (3, 4) and (3, -3), the x value repeats.
Functions do not have repeating x values.
The picture shown is not a function.