I'm not sure how to find the second derivative of this:

$\displaystyle f(x) = (x) / (x-1)$

For the 1st derivative I got: $\displaystyle (-1) / [ (x-1)^2 ]$

The answer for the 2nd derivative is: $\displaystyle (2) / [ (x-1)^3 ] $

But I can't see how they got it...

Thanks in advance