Since a function by definition relates inputs to outputs, it is easy to think of these inputs and outputs as pairs of numbers. For example the Centigrade to Fahrenheit table can be represented by the pairs: (-50,-58), (-40,-40), (-30, -22), (-20,-4), (-10,14), (0, 32), (10, 50),(20, 68),(30, 86), (40,104),(50, 122).
These pairs can be graphically represented as points, and then each point drawn on a graph. The values in the point pairs indicate how far the point is away from a set of axes (in this case 2-axes). The horizontal axis is called the x-axis, and the vertical is the y axis. For example the first point is (-50,-58), which means that the x-value is -50 and the y-value -58.
The graph provides a visual description of the relationship.
Here's some generic graph paper you can use for some of the homework questions.
