NEW HERE? LEARN MORE
closeclose
Last visit was: 26 Apr 2024, 21:32 It is currently 26 Apr 2024, 21:32
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 > 7, which of the following is equal to (x^2 + 8x + 16)/(x^2 - 16

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92948
Own Kudos [?]: 619267 [3]
Given Kudos: 81609
Send PM
CAT Tests Forum Quiz Mode
If x > 7, which of the following is equal to (x^2 + 8x + 16)/(x^2 - 16 [#permalink] New post   11 Dec 2015, 08:49
1
Kudos
1
Bookmarks
Expert Reply
00:00
A
B
C
D
E

Difficulty:

5% (low)

Question Stats:

96% (01:05) correct 4% (01:39) wrong based on 294 sessions
Hide Show timer Statistics
If x > 7, which of the following is equal to (x^2 + 8x + 16)/(x^2 - 16) ?

A. (x + 4)/(4(x - 4))
B. (x - 4)/(x + 4)
C. (x - 2)/(x + 4)
D. (x + 4)/(x - 4)
E. (x - 8)/(x - 4)
ShowHide Answer
Official Answer
D
Most Helpful Reply
User avatar
L
BrentGMATPrepNow
GMAT Club Legend
GMAT Club Legend
Joined: 12 Sep 2015
Posts: 6818
Own Kudos [?]: 29942 [9]
Given Kudos: 799
Location: Canada
Send PM
If x > 7, which of the following is equal to (x^2 + 8x + 16)/(x^2 - 16 [#permalink] New post   Updated on: 29 Jan 2021, 08:55
7
Kudos
2
Bookmarks
Expert Reply
Bunuel wrote:
If x > 7, which of the following is equal to (x^2 + 8x + 16)/(x^2 - 16) ?

A. (x + 4)/(4(x - 4))
B. (x - 4)/(x + 4)
C. (x - 2)/(x + 4)
D. (x + 4)/(x - 4)
E. (x - 8)/(x - 4)


Some readers might be wondering why Bunuel added the part about x > 7.
This is to make the simplification of x^2 + 8x + 16)/(x^2 - 16) mathematically sound.
When we factor this we get (x + 4)(x + 4)/(x + 4)(x - 4)
However, we can't automatically eliminate (x + 4) from top and bottom to conclude that (x + 4)(x + 4)/(x + 4)(x - 4) = (x + 4)/(x - 4)
Why not?
Well, we must first ensure that x does not equal -4.
If x = -4, then (x + 4) = 0, so we are essentially dividing top and bottom by 0, which is not cool.
To avoid this situation, Bunuel stated that x > 7, which means x CANNOT equal -4.

Cheers,
Brent

Originally posted by BrentGMATPrepNow on 12 Dec 2015, 14:44.
Last edited by BrentGMATPrepNow on 29 Jan 2021, 08:55, edited 1 time in total.
General Discussion
User avatar
Divyadisha
Current Student
Joined: 18 Oct 2014
Posts: 680
Own Kudos [?]: 1763 [0]
Given Kudos: 69
Location: United States
GMAT 1: 660 Q49 V31
GPA: 3.98
Send PM
GMAT ToolKit User
Re: If x > 7, which of the following is equal to (x^2 + 8x + 16)/(x^2 - 16 [#permalink] New post   11 Dec 2015, 14:48
IMO 'D' is the answer.
User avatar
B
peachfuzz
Senior Manager
Senior Manager
Joined: 28 Feb 2014
Posts: 269
Own Kudos [?]: 318 [0]
Given Kudos: 132
Location: United States
Concentration: Strategy, General Management
Send PM
Reviews Badge
If x > 7, which of the following is equal to (x^2 + 8x + 16)/(x^2 - 16 [#permalink] New post   12 Dec 2015, 14:26
(x^2 + 8x + 16)/(x^2 - 16)
= (x + 4)(x + 4) / (x + 4)(x - 4)
=(x + 4)/(x - 4)

D. (x + 4)/(x - 4)
User avatar
P
JeffTargetTestPrep
Target Test Prep Representative
Joined: 04 Mar 2011
Status:Head GMAT Instructor
Affiliations: Target Test Prep
Posts: 3043
Own Kudos [?]: 6278 [0]
Given Kudos: 1646
Send PM
Re: If x > 7, which of the following is equal to (x^2 + 8x + 16)/(x^2 - 16 [#permalink] New post   27 Nov 2017, 12:28
Expert Reply
Bunuel wrote:
If x > 7, which of the following is equal to (x^2 + 8x + 16)/(x^2 - 16) ?

A. (x + 4)/(4(x - 4))
B. (x - 4)/(x + 4)
C. (x - 2)/(x + 4)
D. (x + 4)/(x - 4)
E. (x - 8)/(x - 4)


Let’s simplify the given equation:

(x^2 + 8x + 16)/(x^2 - 16)

(x + 4)(x + 4)/[(x - 4)(x + 4)]

(x + 4)/(x - 4)

Answer: D
User avatar
bumpbot
Non-Human User
Joined: 09 Sep 2013
Posts: 32693
Own Kudos [?]: 822 [0]
Given Kudos: 0
Send PM
Re: If x > 7, which of the following is equal to (x^2 + 8x + 16)/(x^2 - 16 [#permalink] New post   26 Feb 2021, 07:42
Top Contributor
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 > 7, which of the following is equal to (x^2 + 8x + 16)/(x^2 - 16 [#permalink]
26 Feb 2021, 07:42
Moderators:
Bunuel
Math Expert
92948 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