vinviper1 wrote:Thanks!

You have to plug in for this one.

I'll try to explain the question as clearly as I can. If f(x)=f(1-x), that means that wherever x works in an equation, you will get the same answer by substituting (x) with (x-1). This question does not give you a clear road map on what the answer will be (it could be anything), so you have to reference the answers TO FIND the answer. Below are the ways you would set up each answer:

A. 1-(1-x)
B. 1-[(1-x)^2]
C. [(1-x)^2]-[1-(1-x)]^2
D. [(1-x)^2][1-(1-x)]^2
E. (x-1)/[1-(x-1)]

Once again, all I am doing is replacing all (x)s with (x-1)s. If you solved each equation, you will find that D is the one that will give you the original equation after substituting (x-1) for x.

Hope this makes sense.

Worked out, here is the answer.

f(x)=[x^2][(1-x)^2]
f(x-1)=[(1-x)^2][1-(1-x)]^2
=[(1-x)^2][0+x]^2
=[(1-x)^2][x]^2
rewritten, =[x^2][(1-x)^2]

Once again, even though we substituted all (x)s with (x-1)s, we still got the same equation as before! Hope this is cool! Yay for math, haha!! ....... damn, GMAT prep turned me into a nerd..