
Answer:
A relation is not a function if it repeats its input values, or x values.
Step-by-step explanation:
For example, the relation 4,3 3,6 7,5 ,3,8 would not be a function because it repeats the x value of 3 in the points 3,6 and 3,8.
The relation 4,3 3,6 7,5 and 8,3 would be a function because it does not repeat the input values.
Hope this helps!