# Is (5, -2), (5, -1), (5, 0), (5, 1) a function?

Jun 11, 2018

A function is an expression in terms of a variable, usually x. Hence, that is not a function.

#### Explanation:

What you have there are four sets of coordinates. They may have all come from the same function, but they are not themselves a function as there is no x term involved.

Function notation is essentially the same as graphical notation, but instead of 'y =' we write 'f(x) ='. This is more useful as it allows transformations applied to the function (or graph) to be easily seen, and can also be used out of the context of graph. A function is shown below to illustrate this.

$f \left(x\right) = {x}^{2} + 9$

Jun 11, 2018

No. See explanation.

#### Explanation:

A set of points could be a function if each $x$ value appeared only once in it.

The given set of pairs has only one $x$ coordinate ($5$). There are $4$ different values assigned to it, so this assignment is not a function.