this week in math 10 I learned how to identify if a relation is a function. I learned that for a relation to be a function, it basically means that the input must have only have one output. on graph, a function would not have any dots sitting directly above each other:

where as in this graph does not represent a function because there are two points vertically above each other

you can also represent functions through mapping diagrams, a mapping diagram uses arrows to connect the inputs with the outputs, an example of a relation that is not a function would be this because 4, as you can see has arrows to three different outputs.

however this diagram represents a function because it is showing that every input number only has one output/one connecting arrow