Question

What is a function?

Answer 1

A function is a set of ordered pairs (points) formed from a defining equation, where, for each `x`-value there is only one `y`-value.

Explanation:

`x-------> y` represents a function

This means that you can choose an `x`-value and plug it into an equation, usually given as:

`y= ....." " or" " f(x)= .....`

This will give you a `y`-value.

In a function there will be only ONE possible answer for `y`.

If you find you have a choice, then the equation does not represent a function.

The following are functions:

`y=-3`

`y=3x-5`

`y = 2x^2-3x+1`

`(1,2), (2,2), (3,2),(4,2)`

The following are NOT functions:

`x= 3`

`y=+-sqrt(x+20)`