I can't seem to figure out a problem in one of my assignments. The question is:

Suppose a, b, c, and d are integers and a does not equal c. Suppose also that x is a real number that satisfies the equation

(ax+b)/(cx+d) = 1.

Must x be rational? If so, express x as a ratio of two integers.

So does that mean b can equal d? Confused on how to start it.(Headbang)