Events & Promotions
|
|
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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Apr 2610:00 AM EDT
-11:00 AM EDT
The Target Test Prep course represents a quantum leap forward in GMAT preparation, a radical reinterpretation of the way that students should study. Try before you buy with a 5-day, full-access trial of the course for FREE!
Apr 2711:00 AM EDT
-12:00 PM EDT
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors
Apr 2808:00 AM PDT
-11:00 AM PDT
Whether you are just beginning your MBA journey or fine-tuning your path to a 700+ score, GMAT Day is designed to give you a competitive edge.
04 Jun 2018, 23:21
Kudos
Bookmarks
Hi ,
so some algebra questions require that we divide by a variable .
When can we do that safely ?
my concern is that the value of the variable could be 0 ;we cannot divide by 0 .
What if we are NOT told that the value is not 0 ? Can we still divide , assuming that it is not 0 ?
here are an example that requires to divide by a variable ,
Source : Manhatten
so some algebra questions require that we divide by a variable .
When can we do that safely ?
my concern is that the value of the variable could be 0 ;we cannot divide by 0 .
What if we are NOT told that the value is not 0 ? Can we still divide , assuming that it is not 0 ?
here are an example that requires to divide by a variable ,
Source : Manhatten
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!
Attachments
666.JPG [ 12.37 KiB | Viewed 1632 times ]
05 Jun 2018, 09:38
Kudos
Bookmarks
foryearss
Never reduce equation by a variable (or expression with variable), if you are not certain that the variable (or expression with the variable) doesn't equal to zero.
For the question at hand though neither x nor y can be 0 for two reasons:
We are given that \(xy^2 = -96\). If x or y were 0, then \(xy^2\) would be 0, not -96.
We are also given that \(\frac{1}{xy} = \frac{1}{24}\). If x or y were 0, then \(\frac{1}{xy}\) would be undefined and could not equal to 1/24.
SOLUTION:
If \(xy^2 = -96\) and \(\frac{1}{xy} = \frac{1}{24}\), what is y?
Multiply those two equations: \(xy^2*\frac{1}{xy} = -96*\frac{1}{24}\):
\(y=-4\)
Hope it helps.
05 Jun 2018, 10:44
Kudos
Bookmarks
Quote:
so if we have a fraction , a variable in the denominator , we can assume safely that the denominator will NOT equal to 0 ?
because then the fraction will be undefined
For example :
(x-2)/ x^2-4 = x-2 / (x+2)(x-2)
now at this point , can we divide by x-2 ?
( neither we are told clearly that x cannot equal to 2 , nor we can conclude that info from the question as you did above)
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!
