If x and y are different integers, both divisible by 7, then which is not necessarily true?
Choose the most appropriate option: A) x^2 + y^2 is divisible by 7 B) x - y is divisible by 7 C) xy is divisible by 7 D) x + y is divisible by 7 E) x + y is divisible by 14
Let x = 7k and let y = 7j.   Then x+y = 7(k+j) and k+j could be even or odd.   Thus 7(k+j) is not necessarily divisible by 14.   The answer is x + y is divisible by 14.
<result>E</result>
If x and y are different integers, both divisible by 7, then which is not necessarily true?