It is currently 24 Nov 2017, 06:23

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

If x^2 − kx + 24 = 0, is x = −6?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

1 KUDOS received
Current Student
User avatar
Joined: 03 Feb 2013
Posts: 941

Kudos [?]: 1079 [1], given: 548

Location: India
Concentration: Operations, Strategy
GMAT 1: 760 Q49 V44
GPA: 3.88
WE: Engineering (Computer Software)
Reviews Badge
If x^2 − kx + 24 = 0, is x = −6? [#permalink]

Show Tags

New post 05 Nov 2014, 09:20
1
This post received
KUDOS
6
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  85% (hard)

Question Stats:

42% (01:20) correct 58% (01:17) wrong based on 132 sessions

HideShow timer Statistics

If x^2 − kx + 24 = 0, is x = −6?

(1) (x+6) is a factor of x^2-k·x+24=0, where k is a constant, and x is a variable.

(2) (x+4) is a factor of x^2-k·x+24=0, where k is a constant, and x is a variable.
[Reveal] Spoiler: OA

_________________

Thanks,
Kinjal
My Debrief : http://gmatclub.com/forum/hardwork-never-gets-unrewarded-for-ever-189267.html#p1449379
My Application Experience : http://gmatclub.com/forum/hardwork-never-gets-unrewarded-for-ever-189267-40.html#p1516961
Linkedin : https://www.linkedin.com/in/kinjal-das/

Please click on Kudos, if you think the post is helpful

Kudos [?]: 1079 [1], given: 548

Current Student
User avatar
Joined: 03 Feb 2013
Posts: 941

Kudos [?]: 1079 [0], given: 548

Location: India
Concentration: Operations, Strategy
GMAT 1: 760 Q49 V44
GPA: 3.88
WE: Engineering (Computer Software)
Reviews Badge
Re: If x^2 − kx + 24 = 0, is x = −6? [#permalink]

Show Tags

New post 05 Nov 2014, 09:24
x^2−k·x+24=0
Solving the equation we get x = -6 or -4

Statement 1)
(1) (x+6) is a factor of x^2-k·x+24=0, where k is a constant, and x is a variable.
We already know that (x+6) is a factor of equation. No new information to determine if x = -6

2) (x+4) is a factor of x^2-k·x+24=0, where k is a constant, and x is a variable.
We already know that (x+4) is a factor of equation. No new information to determine if x = -6

Combining.
(x+6) and (x+4) are factors -> No new information to determine if x = -6
hence E)
_________________

Thanks,
Kinjal
My Debrief : http://gmatclub.com/forum/hardwork-never-gets-unrewarded-for-ever-189267.html#p1449379
My Application Experience : http://gmatclub.com/forum/hardwork-never-gets-unrewarded-for-ever-189267-40.html#p1516961
Linkedin : https://www.linkedin.com/in/kinjal-das/

Please click on Kudos, if you think the post is helpful

Kudos [?]: 1079 [0], given: 548

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42356

Kudos [?]: 133204 [0], given: 12439

Re: If x^2 − kx + 24 = 0, is x = −6? [#permalink]

Show Tags

New post 05 Nov 2014, 09:36
kinjiGC wrote:
If x^2−kx+24=0, is x=−6?

(1) (x+6) is a factor of x^2-k·x+24=0, where k is a constant, and x is a variable.

(2) (x+4) is a factor of x^2-k·x+24=0, where k is a constant, and x is a variable.


Similar question to practice: if-x-2-12x-k-0-is-x-155465.html
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 133204 [0], given: 12439

Manager
Manager
avatar
Joined: 02 May 2014
Posts: 116

Kudos [?]: 63 [0], given: 475

Schools: ESADE '16, HKU'16, SMU '16
GMAT 1: 620 Q46 V30
GMAT ToolKit User
Re: If x^2 − kx + 24 = 0, is x = −6? [#permalink]

Show Tags

New post 05 Nov 2014, 12:00
Hi kinjiGC ,
How did u derive the values x = -6 or x = -4 from the question stem itself ? Can u please elaborate ?

Kudos [?]: 63 [0], given: 475

Manager
Manager
avatar
B
Joined: 27 Aug 2014
Posts: 102

Kudos [?]: 119 [0], given: 19

Concentration: Finance, Strategy
GPA: 3.9
WE: Analyst (Energy and Utilities)
Re: If x^2 − kx + 24 = 0, is x = −6? [#permalink]

Show Tags

New post 23 Nov 2014, 10:01
I think it is not possible to get the solution of the equation from stem as specified by kinji:

from statement 1:
x+6 is a factor of x^2-kx+24 = 0, substitute x = -6 and we get the value of k as -10 , from this the roots of the equation
x^2-10x+24 = 0 are -4 and -6, so NSF
from statement 2:
we have the same result NSF
combined x = -4 or -6 so, NSF

E

Kudos [?]: 119 [0], given: 19

Manager
Manager
avatar
B
Joined: 26 Jan 2016
Posts: 52

Kudos [?]: 1 [0], given: 42

Location: India
Concentration: General Management, Statistics
GMAT 1: 670 Q49 V31
GMAT 2: 730 Q49 V41
GPA: 3
WE: Information Technology (Computer Software)
Re: If x^2 − kx + 24 = 0, is x = −6? [#permalink]

Show Tags

New post 08 Oct 2017, 03:14
For x2−k·x+24=0, pairs of roots can be (-6,-4),(6,4),(-12,-2) and (-8,-3) etc.
1) We have been told that (x+6) is a root so our pair is (-6,-4). Here two values of x can be possible. Not Sufficient.
2) Same as statement 1.

1& 2 together not sufficient.

Kudos [?]: 1 [0], given: 42

Re: If x^2 − kx + 24 = 0, is x = −6?   [#permalink] 08 Oct 2017, 03:14
Display posts from previous: Sort by

If x^2 − kx + 24 = 0, is x = −6?

  new topic 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 | 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®.