Question

Which is a function?

Answer 1

1. Function
2. Not a function
3. Function
4. Not a function

Explanation:

You want to know which of the relations shown is a function.

Function

The rule is pretty simple. A relation is a function if each element of the domain maps to exactly one range value.

If an element of the domain maps to two or more range values, the relation is not a function.

In the attachment, we have identified what you would look for to determine that the relation is not a function. The map of a function has one arrow from each domain value. The ordered pairs of a function have no repeated first-values.