It is currently 21 Apr 2019, 10:04

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# (–x + y)(–y + x) = x2 – y2 y2 – x2 0 –(x – y)2 (y – x)2

Author Message
TAGS:
GRE Prep Club Legend
Joined: 07 Jun 2014
Posts: 4857
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 106

Kudos [?]: 1820 [0], given: 397

(–x + y)(–y + x) = x2 – y2 y2 – x2 0 –(x – y)2 (y – x)2 [#permalink]  15 Apr 2018, 03:49
Expert's post
00:00

Question Stats:

100% (00:10) correct 0% (00:00) wrong based on 2 sessions
$$(-x + y)(-y + x) =$$

A. $$x2 - y2$$
B. $$y^2 - x^2$$
C. 0
D. $$-(x - y)^2$$
E. $$(y - x)^2$$

Drill 2
Question: 7
Page: 511

_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

Director
Joined: 07 Jan 2018
Posts: 620
Followers: 7

Kudos [?]: 569 [1] , given: 88

Re: (–x + y)(–y + x) = x2 – y2 y2 – x2 0 –(x – y)2 (y – x)2 [#permalink]  16 Apr 2018, 02:29
1
KUDOS
expand the expression

$$(-x + y)(-y + x) = xy -x^2 -y^2 + xy$$
or, $$(-x + y)(-y + x) = 2xy -x^2 - y^2$$
or, $$(-x + y)(-y + x) = -(-2xy + x^2 + y^2)$$
The expression inside the bracket is similar to $$(a-b)^2$$ so in that format
The expression reduces to $$-(x - y)^2$$
option D
_________________

This is my response to the question and may be incorrect. Feel free to rectify any mistakes

GRE Prep Club Legend
Joined: 07 Jun 2014
Posts: 4857
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 106

Kudos [?]: 1820 [0], given: 397

Re: (–x + y)(–y + x) = x2 – y2 y2 – x2 0 –(x – y)2 (y – x)2 [#permalink]  22 Apr 2018, 12:16
Expert's post
Explanation

Factor out $$-1$$ from the parentheses on the left and rearrange the expression in the parentheses on the right to get $$-1(x - y) (x - y) = -(x - y)^2$$. The answer is choice (D).
_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

Re: (–x + y)(–y + x) = x2 – y2 y2 – x2 0 –(x – y)2 (y – x)2   [#permalink] 22 Apr 2018, 12:16
Display posts from previous: Sort by