A(=abcde) is a 5-digit natural number with no leading zeros and e>a. B(=eca), 3-digit natural number is a multiple of 9 while C(=db), 2-digit natural number is a multiple of 3 but not 9.
Show that x⁵-y⁵=A has no integer solutions if sum of digits of C is not 6.

Note: A(=abcde) means Ten Thousand's digit of A:a, Thousand's digit of A:b and so on unit's digit of A:e.

For the equation take modulo 11 on both sides.
Now evaluate A mod 11.

Posted by Praneeth on 2007-09-17 00:32:58