How do you know this is a function: (-2,10) (4,1) (9,-4) (3,2) (0,-9)?

1 Answer
Apr 8, 2016

The given points all have different x-coordinates.


Recall that a function is a relationship where an inputted number gives only one output number. If there are two or more outputs for a given input, the relationship does not represent a function.

In your case, since each x-coordinate in the given points has only one y-coordinate, these points would represent a function.

However, if there was an added point that had an x-coordinate of any of the given points, the relationship would not represent a function since there would be two points with the #color(red)("same x-coordinate")# but #color(green)("different y-coordinate")#.

For example:

  • represents a function

  • does not represent a function