basically what you have to do is to make up some random pairs that would fit to the task requirements and just remember that at least one domain from these five pairs has to be the same (in my example you have (1,1) and (1,8)), therefore these five ordered pairs do not model a function because domain 1 has two different values.
for example: { (1,1), (2,3), (5,-9), (1,8), (15,4)}
