If a is even and b is even, then their product ab is
A)even.
B)negative.
C)odd.
D)positive.
E)zero.
Which expression has an odd integer value for all integers x and y?
A) x + 2y
B) 3x + 2y
C) 3xy + 5y
D) x^2 + 2y
E) 2xy^2 + 1
First one......the product of two evens is always even
Second one........the answer isn't obvious....but consider that 2 times anything = an even....and adding 1 to this will produce an odd........so (E)
1. The correct answer is even. Two even numbers multiplied together will always yield an even number.