Let be the number of ordered solutions satisfying:
;
;
Prove that is odd.
Solution
1. Consider the general form of the equation:
where .
2. **Count the solutions where :**
If is a solution, then is also a solution. These pairs are distinct and thus the number of such solutions is even.
3. **Consider the case where :**
The equation simplifies to:
Similarly, if is a solution, then is also a solution, making the number of such solutions even.
4. **Consider the case where and :**
The equation further simplifies to:
Again, if is a solution, then is also a solution, making the number of such solutions even.
5. **Consider the case where , , and :**
The equation now becomes:
Solving for , we get:
6. **Find the integer solutions to :**
The integer pairs that satisfy this equation are:
This gives us the solutions:
7. Count the total number of solutions:
Since the number of solutions where and other similar cases are even, and we have exactly 3 solutions where , the total number of solutions is odd.