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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 350,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

If 5x – 5x - 3 = (124)(5y), what is y in terms of x? A. x B. x - 6 C. x - 3 D. 2x + 3 E. 2x + 6 Answer:

Question should read:

If 5^x – 5^(x- 3) = 124*5^y, what is y in terms of x? A. x B. x - 6 C. x - 3 D. 2x + 3 E. 2x + 6

\(5^x-5^{x-3}=124*5^y\) --> factor out \(5^{x-3}\): \(5^{x-3}(5^3-1)=124*5^y\) --> \(5^{x-3}=5^y\) --> bases are equal so we can equate the powers: \(y=x-3\).

Answer: C.

alltimeacheiver format the questions correctly. _________________

If 5x – 5x - 3 = (124)(5y), what is y in terms of x? A. x B. x - 6 C. x - 3 D. 2x + 3 E. 2x + 6 Answer:

Question should read:

If 5^x – 5^(x- 3) = 124*5^y, what is y in terms of x? A. x B. x - 6 C. x - 3 D. 2x + 3 E. 2x + 6

\(5^x-5^{x-3}=124*5^y\) --> factor out \(5^{x-3}\): \(5^{x-3}(5^3-1)=124*5^y\) --> \(5^{x-3}=5^y\) --> bases are equal so we can equate the powers: \(y=x-3\).

Answer: C.

alltimeacheiver format the questions correctly.

Hi Bunuel, I', trying to understand your factorization, but I find some troubles when I have to factorize some value with exponent an expression like in the question (x-3 or x+4), Could you explain me that or do you have a deck where I could dive into this argument? Thank you in advance

If 5x – 5x - 3 = (124)(5y), what is y in terms of x? A. x B. x - 6 C. x - 3 D. 2x + 3 E. 2x + 6 Answer:

Question should read:

If 5^x – 5^(x- 3) = 124*5^y, what is y in terms of x? A. x B. x - 6 C. x - 3 D. 2x + 3 E. 2x + 6

\(5^x-5^{x-3}=124*5^y\) --> factor out \(5^{x-3}\): \(5^{x-3}(5^3-1)=124*5^y\) --> \(5^{x-3}=5^y\) --> bases are equal so we can equate the powers: \(y=x-3\).

Answer: C.

alltimeacheiver format the questions correctly.

Hi Bunuel, I', trying to understand your factorization, but I find some troubles when I have to factorize some value with exponent an expression like in the question (x-3 or x+4), Could you explain me that or do you have a deck where I could dive into this argument? Thank you in advance

Re: If 5^x – 5^(x- 3) = 124*5^y, what is y in terms of x? [#permalink]
28 Mar 2015, 22:00

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. _________________

Re: If 5^x – 5^(x- 3) = 124*5^y, what is y in terms of x? [#permalink]
29 Mar 2015, 07:10

Expert's post

alltimeacheiver wrote:

If 5^x – 5^(x- 3) = 124*5^y, what is y in terms of x?

A. x B. x - 6 C. x - 3 D. 2x + 3 E. 2x + 6

Given that 5^x – 5^(x- 3) = 124*5^y So, 5^(x-3+3) - 5^(x- 3) = 124*5^y So, 5^(x-3) [5^3 - 1] = 124*5^y So, 5^(x-3)*124 = 124*5^y So, 5^(x-3) = 5^y So, x-3 = y

Hey, Last week I started a few new things in my life. That includes shifting from daily targets to weekly targets, 45 minutes of exercise including 15 minutes of yoga, making...

This week went in reviewing all the topics that I have covered in my previous study session. I reviewed all the notes that I have made and started reviewing the Quant...

I started running as a cross country team member since highshcool and what’s really awesome about running is that...you never get bored of it! I participated in...