Determine all possible positive integers x and y such that 3^x-2^y=17.

I looked at the other comments, and they used formulas I couldn't understand to get the same answer I did. I, however, used only a scientific calculator (which I can only use half the functions of as I don't even know what the rest mean), paper and a pencil. I actually spent time calculating exponents, forming theories (for instance, all even exponents of 2, starting at 6 and going up, are divisible by three), and testing hypotheses. I tried all even exponents of 2 from 6 to 36.

Posted by Lillian on 2006-08-28 14:30:35