Answer:
2.5%
Step-by-step explanation:
656 / 640 = 1.025
1.025 into percent is 102.5%
102.5% - 100% = 2.5
640 + 2.5% of 640 = 656
BOOM


will be a factor whenever the remainder term

vanishes. But this will never happen for any integer

, so I suspect the question is inaccurately posed. Are there some characters missing?
Answer:
X = 7
Step-by-step explanation: