1. The problem statement, all variables and given/known data Suppose y = 9(x - 3) + 30 is the tangent line to f(x) at x = 3. The limit I need to find: http://img259.imageshack.us/img259/2963/b3275332191bc2fc8561357mt3.gif [Broken] 2. No Relevant equations 3. The attempt at a solution Well I know that f(3) is equal to 30. So that means that the numerator will be 30 - 30 and the denominator will be 0. So I can't remember what I need to do to find the exact answer. Is there some way that I can determine what f(x) is? I know f'(3) = 9 and f(3) = 30. I could work backwards and say f(2) is 21, f(1) is 12, f(0) is 3 but that would require that f be linear. How can I find this limit and be sure that it is the right answer?