Last visit was: 24 Apr 2026, 03:05 It is currently 24 Apr 2026, 03:05
Home
Messages
Tests
Schools
Events
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
User avatar
skinsvt
User avatar
Joined: 22 Mar 2007
Last visit: 14 Aug 2007
Posts: 39
Own Kudos:
2
Posts: 39
Kudos: 2
2^x+y/2^x-y=2^6 What is Y? And 72^8/9^3=? Is there any 24 Mar 2007, 09:50
Kudos
Add Kudos
Bookmarks
Bookmark this Post
2^x+y/2^x-y=2^6 What is Y?



And



72^8/9^3=? Is there any easier way to solve than multiplying out?



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
User avatar
mavery
User avatar
Joined: 11 Mar 2007
Last visit: 22 Aug 2009
Posts: 30
Own Kudos:
3
Posts: 30
Kudos: 3
2^x+y/2^x-y=2^6 What is Y? And 72^8/9^3=? Is there any Updated on: 24 Mar 2007, 13:59
Originally posted by mavery on 24 Mar 2007, 10:34.
Last edited by mavery on 24 Mar 2007, 13:59, edited 1 time in total.
Kudos
Add Kudos
Bookmarks
Bookmark this Post
The first one...

Since all of the exponents have a base of 2, we have the following equation:

(x+y)-(x-y)=6
2y=6
y=3

The second one...

We can rewrite the equation as (9^8)(8^8)/(9^3)...
Subtracting the exponents, we are left with (9^5)(8^8)...

What are the answer choices for the second one?
User avatar
Amardeep Sharma
User avatar
Joined: 13 Dec 2006
Last visit: 24 Mar 2019
Posts: 219
Own Kudos:
579
Location: Indonesia
Posts: 219
Kudos: 579
2^x+y/2^x-y=2^6 What is Y? And 72^8/9^3=? Is there any 24 Mar 2007, 10:42
Kudos
Add Kudos
Bookmarks
Bookmark this Post
hi Mavery.. Good explanation but just a small correction,

2y=6
y=2, wrong it will y=3

regards,

Amardeep
User avatar
skinsvt
User avatar
Joined: 22 Mar 2007
Last visit: 14 Aug 2007
Posts: 39
Own Kudos:
2
Posts: 39
Kudos: 2
2^x+y/2^x-y=2^6 What is Y? And 72^8/9^3=? Is there any 24 Mar 2007, 10:45
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Thanks

I honestly don't remember - I saw it on a GMATPrep test this morning. They were something like this...


8^8
8^5
8^3(72^5)
8^5(72^8)
8(72^6)

These are just close guesses. I didn't save the test, but do remember that none of the answers had a 9.
User avatar
amd08
User avatar
Joined: 22 Feb 2007
Last visit: 15 Mar 2008
Posts: 53
Own Kudos:
16
Posts: 53
Kudos: 16
2^x+y/2^x-y=2^6 What is Y? And 72^8/9^3=? Is there any 24 Mar 2007, 11:25
Kudos
Add Kudos
Bookmarks
Bookmark this Post
8^3(72^5) simplifies to 9^5.8^8
User avatar
mavery
User avatar
Joined: 11 Mar 2007
Last visit: 22 Aug 2009
Posts: 30
Own Kudos:
3
Posts: 30
Kudos: 3
2^x+y/2^x-y=2^6 What is Y? And 72^8/9^3=? Is there any 24 Mar 2007, 13:59
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Thanks Amardeep...Those are some of the silly mistakes I'm trying to eliminate...
User avatar
mavery
User avatar
Joined: 11 Mar 2007
Last visit: 22 Aug 2009
Posts: 30
Own Kudos:
3
Posts: 30
Kudos: 3
2^x+y/2^x-y=2^6 What is Y? And 72^8/9^3=? Is there any 24 Mar 2007, 14:02
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Ok skinsvt...we'll pick back up on the second question...we have (9^5)*(8^8)...this is the same as (9^5)*(8^5)*(8^3)=(72^5)*(8^3)
User avatar
skinsvt
User avatar
Joined: 22 Mar 2007
Last visit: 14 Aug 2007
Posts: 39
Own Kudos:
2
Posts: 39
Kudos: 2
2^x+y/2^x-y=2^6 What is Y? And 72^8/9^3=? Is there any 24 Mar 2007, 14:23
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Thanks everyone...Amazing how simple these questions look when you know the answers.



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!