Writing the equation of a transformed exp function given the graph

[needingtoknow]

Homework Statement

EXPONENTIAL FUNCTION

The graph represents a transformation of the function f(x) = 2^x, Write an equation for it.

The graph in question is the second one, graph B.

http://ars.els-cdn.com/content/image/1-s2.0-S0006349598778683-gr1.gif

Since there are more variables involved I am not sure how to solve. I know if its just ab^x then I can find two points and do a system of equations. But what is the process when I have, k, a, d variables to worry about as well. I know that c is 0 because its the asymptote. Can someone please help. Thanks!

 

[haruspex]

There's no way to solve this as a completely open-ended question. You have to make some assumption about the general form of the transformation. Suggest something.