GMAT Changed on April 16th - Read about the latest changes here

It is currently 24 May 2018, 07:07

Happening NOW:

INSEAD Rolling Out R1 Admission Decisions - Join CHAT Room2 to Get Latest Updates from Fellow Applicants


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 + 4)^2)^(1/2) = 3, which of the following could be the value of

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

Hide Tags

1 KUDOS received
Manager
Manager
avatar
B
Joined: 21 Jun 2011
Posts: 75
Location: United States
Concentration: Accounting, Finance
WE: Accounting (Accounting)
If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of [#permalink]

Show Tags

New post Updated on: 25 Dec 2017, 22:55
1
This post received
KUDOS
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

66% (01:07) correct 34% (00:47) wrong based on 169 sessions

HideShow timer Statistics

If \(\sqrt{(x+4)^2} = 3\), which of the following could be the value of x - 4?

A. -11
B. -7
C. -4
D. -3
E. 5

Originally posted by davidfrank on 10 Dec 2012, 01:58.
Last edited by Bunuel on 25 Dec 2017, 22:55, edited 2 times in total.
Renamed the topic and edited the question.
Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 45360
Re: If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of [#permalink]

Show Tags

New post 10 Dec 2012, 02:11
If \(\sqrt{(x+4)^2} = 3\), which of the following could be the value of x - 4?

A. -11
B. -7
C. -4
D. -3
E. 5

\(\sqrt{(x+4)^2} = 3\) --> \((x+4)^2=9\) --> \(x+4=3\) or \(x+4=-3\) --> \(x=-1\) or \(x=-7\) --> \(x-4=-5\) or \(x-4=-11\).

Answer: A.

Hope it's clear.

P.S. Please read carefully and follow: rules-for-posting-please-read-this-before-posting-133935.html Please pay attention to the rule #3. Thank you.
_________________

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

Manager
Manager
avatar
B
Joined: 21 Jun 2011
Posts: 75
Location: United States
Concentration: Accounting, Finance
WE: Accounting (Accounting)
Re: If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of [#permalink]

Show Tags

New post 10 Dec 2012, 02:33
Bunuel wrote:
If \(\sqrt{(x+4)^2} = 3\), which of the following could be the value of x - 4?

A. -11
B. -7
C. -4
D. -3
E. 5

\(\sqrt{(x+4)^2} = 3\) --> \((x+4)^2=9\) --> \(x+4=3\) or \(x+4=-3\) --> \(x=-1\) or \(x=-7\) --> \(x-4=-5\) or \(x-4=-11\).

Answer: A.

Hope it's clear.

P.S. Please read carefully and follow: rules-for-posting-please-read-this-before-posting-133935.html Please pay attention to the rule #3. Thank you.


Bunuel, at 1st place why are you squaring both sides when we know that square root have a value of 1/2 which eventually cancels out the square.
\sqrt{(x+4)^2=3}
so this leaves me with x+4=3
and x=-1.
What is wrong with my approach. I know that I don't have an option of -5 in the answer but still my solution is correct.
Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 45360
Re: If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of [#permalink]

Show Tags

New post 10 Dec 2012, 02:43
davidfrank wrote:
Bunuel wrote:
If \(\sqrt{(x+4)^2} = 3\), which of the following could be the value of x - 4?

A. -11
B. -7
C. -4
D. -3
E. 5

\(\sqrt{(x+4)^2} = 3\) --> \((x+4)^2=9\) --> \(x+4=3\) or \(x+4=-3\) --> \(x=-1\) or \(x=-7\) --> \(x-4=-5\) or \(x-4=-11\).

Answer: A.

Hope it's clear.

P.S. Please read carefully and follow: rules-for-posting-please-read-this-before-posting-133935.html Please pay attention to the rule #3. Thank you.


Bunuel, at 1st place why are you squaring both sides when we know that square root have a value of 1/2 which eventually cancels out the square.
\sqrt{(x+4)^2=3}
so this leaves me with x+4=3
and x=-1.
What is wrong with my approach. I know that I don't have an option of -5 in the answer but still my solution is correct.


That's not correct.

\(\sqrt{x^2} =|x|\) (check here: if-x-3-4-and-y-2-5-what-is-the-value-of-110071.html#p880130), thus \(\sqrt{(x+4)^2} =|x+4|\) not x+4.

From \(|x+4|=3\) --> \(x=-1\) or \(x=-7\).

Hope it's clear.
_________________

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

Intern
Intern
User avatar
Joined: 24 Apr 2012
Posts: 48
Re: If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of [#permalink]

Show Tags

New post 10 Dec 2012, 04:44
Ans: Squaring both the sides we get (x+4)^2=9, therefore (x+4)=3,-3. So (x-4) could be -5 or -11. The answer is (A).
_________________

www.mnemoniceducation.com

TURN ON YOUR MINDS!!!

Expert Post
Target Test Prep Representative
User avatar
G
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 2611
Location: United States (CA)
Re: If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of [#permalink]

Show Tags

New post 30 Jan 2018, 11:23
davidfrank wrote:
If \(\sqrt{(x+4)^2} = 3\), which of the following could be the value of x - 4?

A. -11
B. -7
C. -4
D. -3
E. 5


Simplifying the left hand side of the equation, we have:

|x + 4| = 3

Thus x + 4 = 3, or x + 4 = -3.

If x + 4 = 3, then x = -1, and so x - 4 = -5.

If x + 4 = -3, then x = -7, and so x - 4 = -11.

Since -5 is not one of the answer choices, the answer must be -11.

Answer: A
_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Re: If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of   [#permalink] 30 Jan 2018, 11:23
Display posts from previous: Sort by

If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


cron

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| 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®.