CLEP tests

Okay.. I'm taking a college CLEP test on Thursday. I've been studying for a while. But, I have one question I can't figure out. I know its easy, but since I'm out of school my mind is shut off. I was wondering if anyone could help me understand it.

The question is Which of this following is a factor of 4 - (x+y)^2

A.) - (x+y)^2
B.) x+y
C.) 2 - x+y
D.) 2+x+y
E.) 4+x+y

I know the answer is D, but I've tried almost everyway and I can't seem to crasps how they got it. I was wondering if anyone could explain this to me. Thanks,

Alias

when you multiply the x by the y you get 5 and then you divide it by 2 then add Z then subtract 2, then you add D.

You get your answer

Here is how:

4- (x+y)^2 = 2^2 -(x+y)^2

= [2+(x+y)][2-(x+y)] because a^2-b^2=(a+b)(a-b)

Therefore 2+x+y is a factor...



However for such questions with multiple choices I find it faster to substitute values in place of x & y and then check the choices. In most cases it eliminates the redundant answers. ex. put x=1, y=2 in your problem...note: it does not work with x=1, y=1....



[edit on 20-6-2005 by Quake]

That works too...


I liked my way better...

Thanks, hopefully I will pass. I would hate to have to take that class.