Answer:
A function is a relation that for each input, there is only one output.
Here are mappings of functions. The domain is the input or the x-value, and the range is the output, or the y-value.
Each x-value is related to only one y-value.
Athough the inputs equal to -1 and 1 have the same output, this relation is still a function because each input has just one output.
This mapping is not a function. The input for -2 has more than one output.
I hope that helps. I don't know if it is right or wrong, but good luck :)
