18. is the relation {(3, 5), (–4, 5), (–5, 0), (1, 1), (4, 0)} a function? explain. type your answer below.

It is a function because all the inputs (x values) have one output (y value).

For something to be a function, inputs can only have ONE output, if an input has multiple outputs, it is not a function.

If different inputs have the same output, it is still a function because they don't have the same input value