Let $ a = x - y $ and $ b = x + y $. Then $ ab = 2025 $, and $ x = \fraca + b2 $, $ y = \fracb - a2 $. For $ x $ and $ y $ to be integers, $ a + b $ and $ b - a $ must both be even, which implies $ a $ and $ b $ must be both even or both odd. - Groen Casting