Example TGG.0: Suppose $y$ is a function of $x$ given by the
equation $y = f (x) = 2x+ 3$.
The table, graph, and mapping diagram of this function have been
created using GeoGebra.
Discussion/Explanation:Notice how the points on the graph are paired
with the points on the mapping diagram.
*** Include here more explanation
Martin Flashman, Sept 11,
2013, Created with GeoGebra