x and y are positive integers. If xy + 2x is odd, then which of the following must be even?
Choose the correct choice from the following choices.
A) x B) y +2 C) x + y D) xy − x E) x^2 − y
Given that xy + 2x is odd, which means x(y+2) is odd.   Product of two nos. will be odd only if both the nos. are odd.   Hence x is odd, y+2 is also odd.   y+2 is even. Answer will be y +2.
<result>B</result>
x and y are positive integers. If xy + 2x is odd, then which of the following must be even?