Find lim x->2 (f(x^2+5) - f(9))/(x-2), knowing that f'(x) = 1/x and f(2) = 9.

I am not sure how to solve this. I suppose f(x) = ln(x), but I don't think that helps me, since the textbook hasn't introduced natural logarithm yet, and from what has been covered so far, I am guessing that it can be solved some other way without this knowledge. Evaluating as is obviously generates a zero denominator.

And thats all I can say, I am completely stumped as to where to begin?