Last visit was: 22 Jul 2024, 07:27 It is currently 22 Jul 2024, 07:27
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.

for You

we will pick new questions that match your level based on your Timer History

Your Progress

every week, we’ll send you an estimated GMAT score based on your performance


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.
Request Expert Reply
Confirm Cancel
Show Tags
Hide Tags
Joined: 30 Aug 2015
Posts: 21
Own Kudos [?]: 1388 [2]
Given Kudos: 8
GMAT 1: 570 Q42 V27
GMAT 2: 680 Q50 V35
Send PM
GMAT Club Legend
GMAT Club Legend
Joined: 12 Sep 2015
Posts: 6804
Own Kudos [?]: 30848 [3]
Given Kudos: 799
Location: Canada
Send PM
Joined: 28 Jun 2016
Posts: 153
Own Kudos [?]: 192 [0]
Given Kudos: 99
Location: Canada
Concentration: Operations, Entrepreneurship
Send PM
Magoosh GMAT Instructor
Joined: 28 Dec 2011
Posts: 4490
Own Kudos [?]: 28861 [0]
Given Kudos: 130
Re: What is the value of r^2 - 2rs + s^2? [#permalink]
Expert Reply
inakihernandez wrote:
What is the value of \(r^2 - 2rs + s^2\)?

(1) \(s = 4\)
(2) \(r - s = 12\)

ohmr wrote:
By converting option one to a quadatric equation we get (r-4)& (r-4) as the two roots which means value of R=+ve4. so wouldn't the ans for this q then by D?(both statement suffice)

Dear ohmr,

I'm happy to respond. :-)

My friend, you are relatively new to GMAT Club. When there's something you don't understand about a question, it's much better to post a reply and ask your question. Opening a report only appropriate if you have evidence that the question is wrong (for example, if you are familiar with the book or website where the question appears, and the way it appears here is different from the source). If it's just your own opinion that the answer is different, please discuss that in the thread itself--don't post a report.

My friend you are confused about a subtlety that confuses many people---the difference between an algebraic expression vs. an algebraic equation.
I. an algebraic expression: \(x^2 - 4x - 21\)
The variable x could take on any value on the number line, and for different values of x, this expression would take different values. In fact, we could set y equation to this expression and get the graph of a parabola.
II. an algebraic equation: \(x^2 - 4x - 21 = 0\)
Unlike (I), this is a complete mathematical sentence. On the entire number line, x = -3 and x = +7 are the only two values that satisfy the equation. These are the two values that solve the equation.

Notice that we can solve an equation---we can solve an expression!

This DS is about finding the value of an expression. It gives us an expression with two variables, and asks us to find the value of this expression.

You were treating it as if were about solving an equation, rather than evaluating an expression.

Does this distinction make sense?
Mike :-)
User avatar
Non-Human User
Joined: 09 Sep 2013
Posts: 34035
Own Kudos [?]: 853 [0]
Given Kudos: 0
Send PM
Re: What is the value of r^2 - 2rs + s^2? [#permalink]
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
Re: What is the value of r^2 - 2rs + s^2? [#permalink]
Math Expert
94509 posts