How would you solve this question:

The graph of y=f(x) is expanded vertically about the line y=k by a factor of 5. The point (-3,2) on the graph of y=f(x) has its image under the transformation at the point (-3,22). Find the value of k.

The only way I know how to solve this is with guess and check. >_<

Is there a faster and easier way to solve it?