This relates to functions. My class went over this some time ago but I don't think I was very sure about this and as of right now can't recall how to do this. (Math isn't a natural strong point of mine I don't think)

Lets say I have a graph. From this graph I make some X,Y pairs onto a table. How do I take the information on the table and turn it into a y= formula?

In my notes I have a y=ab^(x/c) formula, where it says A is the vertical intercept (where it crosses the Y axis), B is the Constant ratio, and C is the change in input. At the time it made sense but I failed to put decent explanation for myself in the future. I do know this is the formula for an exponential function.

Am I right in the assumption that b, the constant ratio, is the ratio of change between output? (For instance, if the output goes 10, 30, 90, the ratio is 3) And how do I find the change in input, as that can be irregular?

M.