NEW HERE? LEARN MORE
closeclose
Last visit was: 25 Apr 2024, 12:20 It is currently 25 Apr 2024, 12:20
Decision Tracker
My Rewards
New posts
New comers' posts

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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

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

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
B
davidfrank
Intern
Intern
Joined: 21 Jun 2011
Posts: 48
Own Kudos [?]: 109 [12]
Given Kudos: 15
Location: United States
Concentration: Accounting, Finance
WE:Accounting (Accounting)
Send PM
If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of [#permalink] New post   Updated on: 25 Dec 2017, 22:55
2
Kudos
10
Bookmarks
00:00
A
B
C
D
E

Difficulty:

25% (medium)

Question Stats:

71% (01:22) correct 29% (01:27) wrong based on 484 sessions
Hide Show 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
ShowHide Answer
Official Answer
A

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.
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92914
Own Kudos [?]: 619001 [0]
Given Kudos: 81595
Send PM
CAT Tests Forum Quiz Mode
Re: If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of [#permalink] New post   10 Dec 2012, 02:11
Expert Reply
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.
User avatar
B
davidfrank
Intern
Intern
Joined: 21 Jun 2011
Posts: 48
Own Kudos [?]: 109 [0]
Given Kudos: 15
Location: United States
Concentration: Accounting, Finance
WE:Accounting (Accounting)
Send PM
Re: If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of [#permalink] 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.
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92914
Own Kudos [?]: 619001 [0]
Given Kudos: 81595
Send PM
CAT Tests Forum Quiz Mode
Re: If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of [#permalink] New post   10 Dec 2012, 02:43
Expert Reply
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.
User avatar
priyamne
Intern
Intern
Joined: 24 Apr 2012
Posts: 37
Own Kudos [?]: 49 [0]
Given Kudos: 1
Send PM
Re: If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of [#permalink] 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).
User avatar
L
ScottTargetTestPrep
Target Test Prep Representative
Joined: 14 Oct 2015
Status:Founder & CEO
Affiliations: Target Test Prep
Posts: 18761
Own Kudos [?]: 22052 [0]
Given Kudos: 283
Location: United States (CA)
Send PM
Re: If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of [#permalink] New post   30 Jan 2018, 11:23
Expert Reply
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
avatar
B
drwharton3900
Intern
Intern
Joined: 02 Jul 2020
Posts: 4
Own Kudos [?]: 0 [0]
Given Kudos: 4
Send PM
If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of [#permalink] New post   Updated on: 07 Aug 2020, 23:58
Use the Plug in Method In put Option a -11

-11+4=-7
7^2 =49
sqr rt of 49 = 7

7-4= 3 which matches with 3 stated in Question :) CHeeers yashikaaggarwal

Originally posted by drwharton3900 on 07 Aug 2020, 23:57.
Last edited by drwharton3900 on 07 Aug 2020, 23:58, edited 1 time in total.
User avatar
bumpbot
Non-Human User
Joined: 09 Sep 2013
Posts: 32676
Own Kudos [?]: 822 [0]
Given Kudos: 0
Send PM
Re: If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of [#permalink] New post   27 Jun 2022, 06:09
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 Club Bot
gmatclubot
Re: If ((x + 4)^2)^(1/2) = 3, which of the following could be the value of [#permalink]
27 Jun 2022, 06:09
Moderators:
Bunuel
Math Expert
92914 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions