I need to find the most common anti-derivative of f '' (x) = x^-2 , where x > 0, f(1) = 0 and f(2) = 0

As usual, this is how far I've gotten:

f'(x) = - x^-1 + C

f(x) = -Inx + Cx + D

I think that's right. Now what am I supposed to do?

I tried finding f(1) and f(2) of the function f(x) but it's not coming out as it should.

The answer is supposed to be f(x) = -Inx + (In2)x - In2