It is currently 13 Dec 2017, 05:17

Decision(s) Day!:

CHAT Rooms | Ross R1 | Kellogg R1 | Darden R1 | Tepper R1


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

What is the value of x? (1) x^4+x^2+1=(1/x^4+x^2+1) (2)

  post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Manager
Manager
avatar
Joined: 30 Mar 2007
Posts: 177

Kudos [?]: 45 [0], given: 0

What is the value of x? (1) x^4+x^2+1=(1/x^4+x^2+1) (2) [#permalink]

Show Tags

New post 15 May 2007, 18:48
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

What is the value of x?
(1) x^4+x^2+1=(1/x^4+x^2+1)
(2) x3+x^2=0

What is the greatest integer n such that 13/n is an integer for all consecutive even integers r and s?
A. 10
B. 8
C. 6
D. 4
E. 2

Kudos [?]: 45 [0], given: 0

Manager
Manager
User avatar
Joined: 30 Mar 2007
Posts: 213

Kudos [?]: 14 [0], given: 0

 [#permalink]

Show Tags

New post 15 May 2007, 19:12
both the que are not clear to me...
james
in first que
(1) x^4+x^2+1=(1/x^4+x^2+1) or x^4+x^2+1=1/(x^4+x^2+1)
(2) x3+x^2=0 or x^3+x^2=0

second que also i am clueless...help

Kudos [?]: 14 [0], given: 0

Director
Director
User avatar
Joined: 26 Feb 2006
Posts: 900

Kudos [?]: 165 [0], given: 0

Re: prep questions [#permalink]

Show Tags

New post 15 May 2007, 19:17
Jamesk486 wrote:
What is the value of x?
(1) x^4+x^2+1=(1/x^4+x^2+1)
(2) x3+x^2=0


i did not get 1 but 2 is sufficient.

x = -1.


second question: no idea what is the question is about?

Last edited by Himalayan on 15 May 2007, 19:19, edited 1 time in total.

Kudos [?]: 165 [0], given: 0

Manager
Manager
avatar
Joined: 02 May 2007
Posts: 152

Kudos [?]: 5 [0], given: 0

Re: prep questions [#permalink]

Show Tags

New post 15 May 2007, 19:18
Jamesk486 wrote:
What is the value of x?
(1) x^4+x^2+1=(1/x^4+x^2+1)
(2) x3+x^2=0



(A) it is

(1) x^4+x^2+1=(1/x^4+x^2+1)
=> (x^4+x^2+1)^2 = 1
=> x^4 + x^2 + 1 = 1
=> x^4 + x^2 = 0
=> x^2(x^2 + 1) = 0
=> x = 0 => suff

(2) x^3 + x^2 = x^2(x + 1) = 0
=> x = 0 or x = -1 => insuff

Hence, (A)

Kudos [?]: 5 [0], given: 0

Director
Director
User avatar
Joined: 26 Feb 2006
Posts: 900

Kudos [?]: 165 [0], given: 0

Re: prep questions [#permalink]

Show Tags

New post 15 May 2007, 21:42
kirakira wrote:
Jamesk486 wrote:
What is the value of x?
(1) x^4+x^2+1=(1/x^4+x^2+1)
(2) x3+x^2=0



(A) it is

(1) x^4+x^2+1=(1/x^4+x^2+1)
=> (x^4+x^2+1)^2 = 1
=> x^4 + x^2 + 1 = 1
=> x^4 + x^2 = 0
=> x^2(x^2 + 1) = 0
=> x = 0 => suff

(2) x^3 + x^2 = x^2(x + 1) = 0
=> x = 0 or x = -1 => insuff

Hence, (A)


you are correct in statement 2 but st 1 is also insufficient cuz:

=> (x^4+x^2+1)^2 = 1
=> x^4 + x^2 + 1 = -1 or 1.

from 1 and 2, x should be 0.
seems C.

Kudos [?]: 165 [0], given: 0

Director
Director
User avatar
Joined: 13 Mar 2007
Posts: 541

Kudos [?]: 94 [0], given: 0

Schools: MIT Sloan
 [#permalink]

Show Tags

New post 15 May 2007, 21:56
In GMAT,

(x^2)^(1/2) = +x and not -x

as in -

9^(1/2) is always taken as +3

However, when we have a situation x^2 = 9, then we have to take into consideration of x = 3 and x = -3 !

Can also see the same in OG 11TH edition P-126 under Modulus

"note that (x^2)^(1/2) denotes the non-negative square root of x^2"

So if we consider the above, answer A :)

Kudos [?]: 94 [0], given: 0

Manager
Manager
avatar
Joined: 02 May 2007
Posts: 152

Kudos [?]: 5 [0], given: 0

Re: prep questions [#permalink]

Show Tags

New post 15 May 2007, 23:17
Himalayan wrote:
kirakira wrote:
Jamesk486 wrote:
What is the value of x?
(1) x^4+x^2+1=(1/x^4+x^2+1)
(2) x3+x^2=0



(A) it is

(1) x^4+x^2+1=(1/x^4+x^2+1)
=> (x^4+x^2+1)^2 = 1
=> x^4 + x^2 + 1 = 1
=> x^4 + x^2 = 0
=> x^2(x^2 + 1) = 0
=> x = 0 => suff

(2) x^3 + x^2 = x^2(x + 1) = 0
=> x = 0 or x = -1 => insuff

Hence, (A)


you are correct in statement 2 but st 1 is also insufficient cuz:

=> (x^4+x^2+1)^2 = 1
=> x^4 + x^2 + 1 = -1 or 1.

from 1 and 2, x should be 0.
seems C.


(x^4 + x^2 + 1) is always positive.

Kudos [?]: 5 [0], given: 0

Manager
Manager
avatar
Joined: 30 Mar 2007
Posts: 177

Kudos [?]: 45 [0], given: 0

 [#permalink]

Show Tags

New post 16 May 2007, 06:32
What is the value of x?
(1) x^4+x^2+1=(1/x^4+x^2+1)
(2) x^3+x^2=0

the answer is supposed to be A

Kudos [?]: 45 [0], given: 0

Director
Director
User avatar
Joined: 26 Feb 2006
Posts: 900

Kudos [?]: 165 [0], given: 0

Re: prep questions [#permalink]

Show Tags

New post 16 May 2007, 08:07
kirakira wrote:
Himalayan wrote:
kirakira wrote:
Jamesk486 wrote:
What is the value of x?
(1) x^4+x^2+1=(1/x^4+x^2+1)
(2) x3+x^2=0



(A) it is

(1) x^4+x^2+1=(1/x^4+x^2+1)
=> (x^4+x^2+1)^2 = 1
=> x^4 + x^2 + 1 = 1
=> x^4 + x^2 = 0
=> x^2(x^2 + 1) = 0
=> x = 0 => suff

(2) x^3 + x^2 = x^2(x + 1) = 0
=> x = 0 or x = -1 => insuff

Hence, (A)


you are correct in statement 2 but st 1 is also insufficient cuz:

=> (x^4+x^2+1)^2 = 1
=> x^4 + x^2 + 1 = -1 or 1.

from 1 and 2, x should be 0.
seems C.


(x^4 + x^2 + 1) is always positive.


good point and you r right. 8-)

Kudos [?]: 165 [0], given: 0

Intern
Intern
avatar
Joined: 15 Jan 2007
Posts: 38

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

 [#permalink]

Show Tags

New post 16 May 2007, 09:37
for qstn 1 1. is x^8 = 1 and 2. leads to x = 0 or x = -1. ==> x = -1
So answer C

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

  [#permalink] 16 May 2007, 09:37
Display posts from previous: Sort by

What is the value of x? (1) x^4+x^2+1=(1/x^4+x^2+1) (2)

  post reply Question banks Downloads My Bookmarks Reviews Important topics  

Moderator: chetan2u



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

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

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®.