15 POINTS AND BRAINLIEST ANSWER ASAP! Give an example of a set of five ordered pairs that is a function. Given another example of a set of five ordered pairs that is NOT a function. Explain why the first set is a function and why the second set is not a function.

A function y=f(x) has the property that for any x in the domain there is exactly one value for y=f(x).  

We can represent a function as a set of ordered pairs  { (x₁,y₁), (x₂,y₂), ... }.  Any set of ordered pairs where no value appears twice as the first element is a function.  If the same x appears twice (with necessarily different ys because it's a set) that's not a function.

Function example:  { (0,1), (1,3), (2,5), (3,7), (4,-13) }

Non-function example:  { (0,1), (1,3), (2,5), (3,7), (3,-13) }

In the first set no x is duplicated so it represents a function; in the second 3 is the x in two of the pairs; not a function.