PreAlgebra
posted by Cheryl .
Okay so I have no clue how to determine if a relation is a function.
Here is an example can you tell me how to determine this? D:
Example:
Determine whether the relation is a function. {(5,5), (2,5), (0,5), (2,5)}
Thanks in advance

a funcion has a one to one relationship.
here, for each x, it maps into a single distinct y. Each x here maps to a y.
Now, the reverse: is x a function of y? No, because for y=5, x can be 5, 2, 0, or 2. x is not a function of y.
What if you had added the point (5,4)? Then y would not be a function of x, because if x=5, it maps into both 4, and 5. Not a function then 
Thanks