[/quote]

I expanded option B and equated to A(LHS) and the LHS went 0 and then the whole equation stopped making sense and chooce D.

I am wondering why did you not expanded x+y whole square equation?[/quote]

Let's see what happens if we expand

Given:

QUANTITY A: x - y

QUANTITY B: (x + y)²

Expand Quantity B to get:

QUANTITY A: x - y

QUANTITY B: x² + 2xy + y²

Now what can we do?

Whatever we do from here seems more likely to make matters more confusing.

For example, we COULD add y to both quantities to get:

QUANTITY A: x

QUANTITY B: x² + 2xy + y + y²

This doesn't help.

What if we subtract x from both quantities? We get:

QUANTITY A: 0

QUANTITY B: x² + 2xy + y - x + y²

Yikes!!

At this point, we should probably start considering a different approach.

Cheers,

Brent

_________________

Brent Hanneson – Creator of greenlighttestprep.com

Sign up for my free GRE Question of the Day emails