GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 15 Nov 2019, 15:33

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.

Close

Request Expert Reply

Confirm Cancel

If 2 roots of an equation x^2-3x-3=0 are m and n, what is the value of

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Math Revolution GMAT Instructor
User avatar
V
Joined: 16 Aug 2015
Posts: 8141
GMAT 1: 760 Q51 V42
GPA: 3.82
If 2 roots of an equation x^2-3x-3=0 are m and n, what is the value of  [#permalink]

Show Tags

New post 21 Oct 2016, 08:31
1
10
00:00
A
B
C
D
E

Difficulty:

  55% (hard)

Question Stats:

62% (01:40) correct 38% (02:06) wrong based on 130 sessions

HideShow timer Statistics

If 2 roots of an equation x^2-3x-3=0 are m and n, what is the value of m^2+n^2?

A. 10
B. 12
C. 15
D. 24
E. 25

* A solution will be posted in two days.

_________________
MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only $79 for 1 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"
Math Revolution GMAT Instructor
User avatar
V
Joined: 16 Aug 2015
Posts: 8141
GMAT 1: 760 Q51 V42
GPA: 3.82
Re: If 2 roots of an equation x^2-3x-3=0 are m and n, what is the value of  [#permalink]

Show Tags

New post 26 Oct 2016, 02:56
3
1
==>From x^2-3x-3=(x-m)(x-n)=x^2-(m+n)x+mn, you get m+n=3 and mn=-3. Then you get m^2+n^2=(m+n)^2-2mn=3^2-2*(-3)=15. The answer is C.

Answer: C
_________________
MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only $79 for 1 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"
Math Revolution GMAT Instructor
User avatar
V
Joined: 16 Aug 2015
Posts: 8141
GMAT 1: 760 Q51 V42
GPA: 3.82
Re: If 2 roots of an equation x^2-3x-3=0 are m and n, what is the value of  [#permalink]

Show Tags

New post 04 Nov 2016, 01:31
1
AK125 wrote:
Can someone post a step by step solution pls...Kudos for this


Hi AK125,

x^2-3x-3=(x-m)(x-n)=x^2-(m+n)x+mn so, m-n=3 and mn=-3

Thank you.
_________________
MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only $79 for 1 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"
Manager
Manager
avatar
B
Joined: 28 Jun 2016
Posts: 206
Location: Canada
Concentration: Operations, Entrepreneurship
If 2 roots of an equation x^2-3x-3=0 are m and n, what is the value of  [#permalink]

Show Tags

New post 21 Oct 2016, 08:52
1
m = x + y

n= x - y

Where x= -b/2a

y= (sqrt(b^2 - 4ac))/2a

m^2+n^2 = 2(x^2 + y^2)


= 2(9/4 + 21/4)

=15

C


Sent from my iPhone using GMAT Club Forum mobile app
Board of Directors
User avatar
D
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4832
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)
GMAT ToolKit User
Re: If 2 roots of an equation x^2-3x-3=0 are m and n, what is the value of  [#permalink]

Show Tags

New post 21 Oct 2016, 09:00
MathRevolution wrote:
If 2 roots of an equation x^2-3x-3 = 0 are m and n, what is the value of m^2+n^2?

A. 10
B. 12
C. 15
D. 24
E. 25

* A solution will be posted in two days.


With acegmat123

That's the perfect and easiest way of solving this question

With (C) hence...

PS : Good question MathRevolution ...
_________________
Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )
Intern
Intern
avatar
Joined: 09 Apr 2016
Posts: 32
Re: If 2 roots of an equation x^2-3x-3=0 are m and n, what is the value of  [#permalink]

Show Tags

New post 30 Oct 2016, 09:08
Can someone post a step by step solution pls...Kudos for this
Manager
Manager
avatar
B
Joined: 20 Apr 2014
Posts: 87
Re: If 2 roots of an equation x^2-3x-3=0 are m and n, what is the value of  [#permalink]

Show Tags

New post 04 Nov 2016, 16:08
It is not clear enough. I miss some step above. please any help ?
Current Student
avatar
B
Joined: 08 Oct 2016
Posts: 49
Re: If 2 roots of an equation x^2-3x-3=0 are m and n, what is the value of  [#permalink]

Show Tags

New post 05 Nov 2016, 03:11
MathRevolution wrote:
==>From x^2-3x-3=(x-m)(x-n)=x^2-(m+n)x+mn, you get m+n=3 and mn=-3. Then you get m^2+n^2=(m+n)^2-2mn=3^2-2*(-3)=15. The answer is C.

Answer: C


I don't understand when you solve for (m^2 + n^2) and use (m+n)^2 - 2mn in its place

Posted from my mobile device
Intern
Intern
avatar
Joined: 09 Apr 2016
Posts: 32
Re: If 2 roots of an equation x^2-3x-3=0 are m and n, what is the value of  [#permalink]

Show Tags

New post 08 Nov 2016, 04:01
1
gillyelephant wrote:
MathRevolution wrote:
==>From x^2-3x-3=(x-m)(x-n)=x^2-(m+n)x+mn, you get m+n=3 and mn=-3. Then you get m^2+n^2=(m+n)^2-2mn=3^2-2*(-3)=15. The answer is C.

Answer: C


I don't understand when you solve for (m^2 + n^2) and use (m+n)^2 - 2mn in its place

Posted from my mobile device



We do know m+n which equals 3. And we know mn which is -3.

If we square (m+n) -->

(m+n)^2 = m^2 + 2mn + n^2

Plug in what we do know (green):

(3)^2 = m^2 + 2(-3) + n^2
--> 9 = m^2 - 6 + n^2
--> 15 = m^2 + n^2

Hope its clear!
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 13585
Re: If 2 roots of an equation x^2-3x-3=0 are m and n, what is the value of  [#permalink]

Show Tags

New post 27 Aug 2018, 16:47
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: If 2 roots of an equation x^2-3x-3=0 are m and n, what is the value of   [#permalink] 27 Aug 2018, 16:47
Display posts from previous: Sort by

If 2 roots of an equation x^2-3x-3=0 are m and n, what is the value of

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne