Your question presumes that graphs are more informative than equations. Such is a false presumption. There are certain characteristics of functions and relations that are more easily comprehended when the relationship is represented graphically, but there are other situations where it is much easier, and certainly more accurate, to derive the desired information from an equation.
Here is an example:
The equation for the line graphed above is:
Looking at the graph, the slope looks to be approximately 1, but it would take a great deal of effort to produce a precise answer to the question: "What is the slope?" On the other hand, I can tell immediately by examination of the equation that the slope is EXACTLY
Hence, the quality "more informative" is a direct function of the actual content of the question to be asked. Sometimes graphs are more informative and sometimes equations are more informative.
