Question 683926
The x value of 2 maps to y = 3, y = 5 and y = 7 at the same time. So it is NOT a function.


It is only a function when every x value maps to EXACTLY ONE y value.



Note: Let's say that this requirement wasn't part of the definition of a function. If we have (2,3) and (2,5), then what is f(2)? Is it 3? or is it 5? It can't be both at the same time since f(2) is a single number. This is why the definition above is put in place.