For integers x and y, if (x+2)(y+3) is even then 4xy must be divisible by: Select:
A) 4
B) 8
C) 9
D) 10
E) 12
Just looking at the question, (x+2)(y+3) could be even*even, odd*even, or even*odd in order for the whole expression to be even.   However, just looking at 4xy, since x*y will always be an integer, it will always be divisible by 4. 4 divided by 4 is 1, hence preserving x*y.   Answer: A. 4
<result>A</result>
For integers x and y, if (x+2)(y+3) is even then 4xy must be divisible by: