65288;x+y）^2<X^2. Which of the following is

Oldest

Best Reply

Author

Message

TAGS:

Manager

Joined: 04 Dec 2005

Posts: 79

Followers: 1

Kudos [?]: 1 [0], given: 0

65288;x+yï¼‰^2[#permalink]

04 Jun 2006, 08:48

00:00

Question Stats:

0% (00:00) correct

0% (00:00) wrong

based on 0 sessions

（x+y）^2<X^2. Which of the following is possible?

Ⅰ. xy<0

Ⅱ. y（y+2x）<0

Ⅲ. y<X

Director

Joined: 19 Feb 2005

Posts: 508

Location: Milan Italy

Followers: 1

Kudos [?]: 2 [0], given: 0

[#permalink]

04 Jun 2006, 09:30

I'll give it a try
let's first cancel out x^2

y^2+2xy<0

y(y+2x)<0 -> Great! St 2 is TRUE and possible, isn't it?

what follows afterwards is not very reliable

Case I: y<0 and y+2x>0 -> y>-2x -> -y[this is positive]<[the sign flips]2x[if 2x is greater than a positive number, than x is positive]

Great! St 1 is possible because y is negative and x is positive , but this also means that St 3 is possible because a negative number is always smaller than a positive one.

Don't think it is necessary to go ahead with Case II, since the question asks only for possibility, not necessity

Hope this helps and the other guys correct me as long as I'm wrong

_________________

Please allow me to introduce myself: I'm a man of wealth and taste

Joined: 29 Dec 2005

Posts: 1356

Followers: 6

Kudos [?]: 17 [0], given: 0

Re: PS - Inequivality [#permalink]

04 Jun 2006, 10:45

withme wrote:

（x+y）^2<X^2. Which of the following is possible?

Ⅰ. xy<0
Ⅱ. y（y+2x）<0
Ⅲ. y<X

given that
（x+y）^2<X^2
x^2+2xy+y^2<X^2
2xy+y^2<0 ===== st 1 is also true cuz when y^2 is +ve, 2xy must be -ve. so xy<0.
y(2x+y) <0 ===== st 2 is true..

but we do not know which is -ve and +ve. either could be +ve or -ve. so III can be true (however is possible). in that case we can say I, II, III.

Re: PS - Inequivality [#permalink] 04 Jun 2006, 10:45

		Similar topics	Author	Replies	Last post
Similar Topics:	1	If (x+y)^2<x^2, which of the following must be true? I.	arjtryarjtry	3	22 Jul 2008, 00:10
		If (x+y)^2<x^2, which of the following must be true? I.	arjtryarjtry	7	29 Aug 2008, 04:11
		Which of the following	goldgoldandgold	13	27 Sep 2009, 18:35
	14	If \|x\|<x^2 , which of the following must be true?	mehdiov	51	20 Aug 2010, 12:59

65288;x+y）^2<X^2. Which of the following is

Main navigation

GMAT Resources

Partners

MBA Resources

GMAT ® is a registered trademark of the Graduate Management Admission Council ® (GMAC ®). GMAT Club's website has not been reviewed or endorsed by GMAC.

GMAT Courses

Admissions Consulting

65288;x+y）^2<X^2. Which of the following is

65288;x+y）^2<X^2. Which of the following is

Main navigation

GMAT Resources

Partners

MBA Resources