Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

It is currently 27 May 2017, 13:32

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

why do we use a different approach when the absolute value

  post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Senior Manager
Senior Manager
avatar
Joined: 14 Jun 2007
Posts: 398
Followers: 1

Kudos [?]: 15 [0], given: 0

why do we use a different approach when the absolute value [#permalink]

Show Tags

New post 03 Aug 2007, 13:23
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

why do we use a different approach when the absolute value is an inequality?


|x-5| =8

x-5 = -8, x=-3
x-5 =8, x=13


|x-5|<8

x-5<8, x<13

x-5<-8 x<-3 XX wrong!

but instead we do:

-x+5<8>-3

Last edited by anonymousegmat on 03 Aug 2007, 20:33, edited 1 time in total.
Manager
Manager
avatar
Joined: 07 Jul 2007
Posts: 124
Followers: 2

Kudos [?]: 11 [0], given: 0

 [#permalink]

Show Tags

New post 03 Aug 2007, 19:28
becasue of negative number properties .............
Here relationship gets reversed to maintain validity of the equation. For example -7 is bigger than -8.....so if we want to achieve |x-5|<8>-8
Manager
Manager
avatar
Joined: 07 Jul 2007
Posts: 124
Followers: 2

Kudos [?]: 11 [0], given: 0

 [#permalink]

Show Tags

New post 03 Aug 2007, 19:29
i mean to achieve |x-5|<8>-8
Director
Director
User avatar
Joined: 09 Aug 2006
Posts: 521
Followers: 2

Kudos [?]: 96 [0], given: 0

Re: absolute value [#permalink]

Show Tags

New post 04 Aug 2007, 07:37
anonymousegmat wrote:
why do we use a different approach when the absolute value is an inequality?


|x-5| =8

x-5 = -8, x=-3
x-5 =8, x=13


|x-5|<8

x-5<8, x<13

x-5<-8 x<-3 XX wrong!

but instead we do:

-x+5<8>-3


x < -3 will always be wrong.

|x-5|<8

(x-5) < 8
x < 13

Or , - (x-5) < 8
-x +5 < 8
-x <3> -3
Senior Manager
Senior Manager
User avatar
Joined: 24 Nov 2006
Posts: 349
Followers: 1

Kudos [?]: 26 [0], given: 0

Re: absolute value [#permalink]

Show Tags

New post 07 Aug 2007, 11:55
anonymousegmat wrote:
why do we use a different approach when the absolute value is an inequality?


|x-5| =8

x-5 = -8, x=-3
x-5 =8, x=13


|x-5|<8

x-5<8, x<13

x-5<-8 x<-3 XX wrong!

but instead we do:

-x+5<8>-3


If you are comfortable with visual reasoning, you could try drawing the xy plane and solving there. In many cases, it's much simpler.
Senior Manager
Senior Manager
avatar
Joined: 14 Jun 2007
Posts: 398
Followers: 1

Kudos [?]: 15 [0], given: 0

Re: absolute value [#permalink]

Show Tags

New post 07 Aug 2007, 14:31
Andr359 wrote:
anonymousegmat wrote:
why do we use a different approach when the absolute value is an inequality?


|x-5| =8

x-5 = -8, x=-3
x-5 =8, x=13


|x-5|<8

x-5<8, x<13

x-5<-8 x<-3 XX wrong!

but instead we do:

-x+5<8>-3


If you are comfortable with visual reasoning, you could try drawing the xy plane and solving there. In many cases, it's much simpler.


yeah, that is what i ended up doing to "prove" it to myself. :o)
Re: absolute value   [#permalink] 07 Aug 2007, 14:31
Display posts from previous: Sort by

why do we use a different approach when the absolute value

  post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.