Calculus problem with tangents

I assume we have to use differentiation to answer this question, since it's what we're learning at the moment, the problem is, I have no idea where to begin with this question...

Consider the curve , for 0 (what "for 0" means, I have no clue).

Show that the sum of the x- and y- intercepts of the tangent line to any point (a,b) on the curve (a,b > 0), is equal to 1.

I expect a question like this may come up on an exam, so I'd really like to understand how to work it out. If I've posted this in the wrong section, I'm sincerely sorry. Any help will be very much appreciated.