Ordered Pair and Functions

Plot the ordered pairs on a graph.  See if that suggests an obvious functional relationship (like a polynomial of some sort, for example).

As long as we're talking about a function of x, a function has to pass what's known as the vertical line test.....this means that we can't have one "x" value associated with two different "y" values.  This would mean that a vertical line would cut the graph in two different places = not a function.

It is possible to have one y value associated with two different x values - think of a parabola that opens upward or downward.......the graph of that parabola is a function.