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# OG

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Manager
Joined: 25 Dec 2011
Posts: 54

Kudos [?]: 55 [1], given: 29

GMAT Date: 05-31-2012

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19 Feb 2012, 09:52
1
KUDOS
In one of the explanations of OG
it is given that x^2 > 1
this means

x>1
and x<-1

how ??
I thought it should be
x>1
and x>-1

Kudos [?]: 55 [1], given: 29

Math Expert
Joined: 02 Sep 2009
Posts: 41890

Kudos [?]: 128793 [0], given: 12183

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19 Feb 2012, 12:13
morya003 wrote:
In one of the explanations of OG
it is given that x^2 > 1
this means

x>1
and x<-1

how ??
I thought it should be
x>1
and x>-1

Yes, x^2>1 means that x<-1 or x>1. You can look at this in another way: x^2>1 is the same as |x|>1 --> x<-1 or x>1.

Following might be helpful in solving inequalities:
x2-4x-94661.html#p731476
inequalities-trick-91482.html
data-suff-inequalities-109078.html
range-for-variable-x-in-a-given-inequality-109468.html?hilit=extreme#p873535
everything-is-less-than-zero-108884.html?hilit=extreme#p868863
_________________

Kudos [?]: 128793 [0], given: 12183

Re: OG   [#permalink] 19 Feb 2012, 12:13
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