Question

Is this a function? Why or why not?

Answer 1

No it is not a function.

Explanation:

No it is not a function.

If we view "Domain" as the input values and "Range" as the output values, by definition, a function is only valid if each input gives one and only one unique value for the output.

In this case, for a Domain (input) of value 12, you get a whole bunch of output possibilities, 1, 2, 5, 7. Hence by definition this is not a function.

Answer 2

This isn’t a function as one element of the domain is paired with multiple elements of the range instead of exactly one. This would lead to a vertical graph, which has an undefined slope.