# Is the set #{(1, 4), (2, 5), (3, 5), (4, 6), (5, 7)}# a function?

##### 1 Answer

Yes, it is a function.

#### Explanation:

A set of ordered pairs (a relation) is a function if and only if there are **not** two pairs with the same first element and different second elements.

Since no two pairs in this set have the same first element, there cannot be pairs with the same first and different second elements.

**Note**

Two more examples: