Five, (17 points) Find the positive integer solutions of the equation
Solution
Five, factoring on the left side, we get
Since , we have:
When , correspondingly, .
Also, since are positive integers, then
Therefore, among the six relationships above, only three can hold:
(1)
(2)
(3)
Solving these, we get .
These are all the positive integer solutions to the equation.
Want a route through all this instead of an archive? The track
puts 2,000 problems in a working order, from AMC 10 level to the IMO shortlist.