Find all School-related info fast with the new School-Specific MBA Forum

It is currently 27 Apr 2015, 09:33

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

If x(x - 5)(x + 2) = 0, is x negative?

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Senior Manager
Senior Manager
avatar
Joined: 12 Mar 2009
Posts: 318
Followers: 1

Kudos [?]: 105 [0], given: 1

GMAT ToolKit User
If x(x - 5)(x + 2) = 0, is x negative? [#permalink] New post 10 May 2009, 11:09
3
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  95% (hard)

Question Stats:

45% (01:00) correct 55% (01:22) wrong based on 71 sessions
If x(x - 5)(x + 2) = 0, is x negative?

(1) x^2 – 7x ≠ 0
(2) x^2 –2x –15 ≠ 0

OPEN DISCUSSION OF THIS QUESTION IS HERE: if-x-x-5-x-2-0-is-x-negative-89304.html
[Reveal] Spoiler: OA
Kaplan Promo CodeKnewton GMAT Discount CodesGMAT Pill GMAT Discount Codes
3 KUDOS received
SVP
SVP
User avatar
Joined: 29 Aug 2007
Posts: 2497
Followers: 57

Kudos [?]: 555 [3] , given: 19

Re: If x(x - 5)(x + 2) = 0, is x negative? [#permalink] New post 12 May 2009, 04:07
3
This post received
KUDOS
vaivish1723 wrote:
If x(x-5)(x+2)=0 is x negative?
1.x^2-7x is not equal to 0
2. x^2-2x-15 is not equal to O.


1. x^2-7x is not equal to 0
x(x-7) is not equal to 0. so x is neither 0 nor 7. insuff.

2. x^2-2x-15 is not equal to O.[/quote]
x^2 - 2x - 15 is not equal to 0.
(x^2 - 5x + 3x - 15) is not equal to 0.
(x - 5) (x + 3) is not equal to 0.
x is neither 5 nor -3.

Togather x must be -2 to have x (x-5) (x+2) = 0. suff.

C.
_________________

Verbal: new-to-the-verbal-forum-please-read-this-first-77546.html
Math: new-to-the-math-forum-please-read-this-first-77764.html
Gmat: everything-you-need-to-prepare-for-the-gmat-revised-77983.html


GT

Manager
Manager
User avatar
Joined: 13 May 2009
Posts: 195
Schools: Stanford, Harvard, Berkeley, INSEAD
Followers: 5

Kudos [?]: 29 [0], given: 1

Re: If x(x - 5)(x + 2) = 0, is x negative? [#permalink] New post 14 May 2009, 13:06
vaivish1723 wrote:
IF x(X-5)(X+2)=0 is x negative?
1.x sq.2-7x is not equal to 0
2. x2-2x-15 is not equal to O.

Please help. OA is [img]c[img]


Fact: \(x(x-5)(x+2)=0\)
Question:( x<0 )?

Interpret fact to get that x=0,5 or -2, in the first 2 cases we have NO, in the last one we have a YES.

So we need more data.

(1) \(x*sqrt(7x) != 0\) (correct me if I read this wrong)
This means that x != 0 & that sqrt(7x) != 0. I don't think this is an Official question (GRRRR) or a very
poorly formulate one, but we can't test x=-2 as the square root of a negative number is a complex number... So if we can use complex numbers, insufficient, and if we aren't allowed to take the square root of a negative number, sufficient, as X can only be 5. But I'm going to go with Insufficient.

(2) \(x^2 - 2x - 15 != 0\)
Factorize the quadratic,
\(x^2 - 5x + 3x - 15 != 0\)
\(x(x - 5) + 3(x - 5) != 0\)
\((x-5)(x+3) !=0\)
So X can't be 5 or -3, but it can still be 0 or -2. Insufficient.

(1&2)
From original equation: x=0,5,-2
1 eliminates 0
2 eliminates 5
Only x=-2 remains

Final Answer, C.
_________________

Hades

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 4684
Followers: 291

Kudos [?]: 52 [0], given: 0

Premium Member
Re: If x(x - 5)(x + 2) = 0, is x negative? [#permalink] New post 19 Dec 2014, 00:20
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 27123
Followers: 4186

Kudos [?]: 40489 [0], given: 5540

Re: If x(x - 5)(x + 2) = 0, is x negative? [#permalink] New post 19 Dec 2014, 02:54
Expert's post
If x(x - 5)(x + 2) = 0, is x negative?

\(x(x - 5)(x + 2) = 0\) --> \(x=0\) or \(x=5\) or \(x=-2\). Question is \(x<0\) or is \(x=-2\)?

(1) x^2 – 7x ≠ 0 --> \(x(x-7)\neq{0}\)--> \(x\neq{0}\) and \(x\neq{7}\), so \(x\) can be 5 or -2 (from the stem as \(x=0\) is out). Not sufficient.

(2) x^2 –2x –15 ≠ 0 --> \((x+3)(x-5)\neq{0}\) --> \(x\neq{-3}\) and \(x\neq{5}\), so \(x\) can be 0 or -2 (from the stem as \(x=5\) is out). Not sufficient.

(1)+(2) As \(x=0\) and \(x=5\) are out, only value left is \(x=-2\), so \(x\) is negative. Sufficient.

Answer: C.

OPEN DISCUSSION OF THIS QUESTION IS HERE: if-x-x-5-x-2-0-is-x-negative-89304.html
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

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?
25 extra-hard Quant Tests

GMAT Club Premium Membership - big benefits and savings

Re: If x(x - 5)(x + 2) = 0, is x negative?   [#permalink] 19 Dec 2014, 02:54
    Similar topics Author Replies Last post
Similar
Topics:
3 Experts publish their posts in the topic If x(x - 5)(x + 2) = 0, is x negative? vaivish1723 5 17 Jan 2010, 09:43
2 If x(x - 5)(x + 2) = 0, is x negative? (1) x2 7x 0 (2) x2 2x crejoc 1 16 Aug 2009, 22:17
1 Experts publish their posts in the topic If x(x-5)(x+2) = 0, is x negative? (1) x^2 - 7x does not TheBigCheese 6 12 Jul 2008, 06:32
If x(x - 5)(x + 2) = 0, is x negative? (1) x2 7x ? 0 smily_buddy 1 22 Jul 2007, 20:17
if x(x-5)(x+2)=0, is x negative? 1)x^2 - 7x >= 0 2) x^2 - imaru 24 09 Oct 2006, 07:42
Display posts from previous: Sort by

If x(x - 5)(x + 2) = 0, is x negative?

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| 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®.