Pairs of points .
Plot the order of pairs on coordinate plane.
\The relation is
The domain of the relation is the set of all first (x-coordinates) coordinates.
\The domain of the relation is:
The range of the relation is the set of second (y-coordinates) coordinates.
\The range of the relation is
Draw the vertical lines through the points. Observe that there is no vertical line contains more than one of the points. This graph passes the vertical line test. Therefore the relation is a function
\Yes.