(3)
If corresponding to each x value, there is only one y value, then the data set represents a function.
(a)
The first term in an ordered pair represents an x coordinate and the second term represents a y coordinate.
In the given set of ordered pairs, for every x value, there is only one y value.
Therefore, the set represents a function.
(b)
In the given data set, corresponding to x=2, there are two y values, y=9 and y=4. For a function, corresponding to one x value, there should be only one y value. Therefore, the given data set does not represent a function.
