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

 It is currently 13 Dec 2018, 23:53

### 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

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

## Events & Promotions

###### Events & Promotions in December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
• ### GMATbuster's Weekly GMAT Quant Quiz, Tomorrow, Saturday at 9 AM PST

December 14, 2018

December 14, 2018

09:00 AM PST

10:00 AM PST

10 Questions will be posted on the forum and we will post a reply in this Topic with a link to each question. There are prizes for the winners.
• ### Typical Day of a UCLA MBA Student - Recording of Webinar with UCLA Adcom and Student

December 14, 2018

December 14, 2018

10:00 PM PST

11:00 PM PST

Carolyn and Brett - nicely explained what is the typical day of a UCLA student. I am posting below recording of the webinar for those who could't attend this session.

# If one root of the equation 2x^2 + 3x – k = 0 is 6, what is the value

Author Message
TAGS:

### Hide Tags

Manager
Joined: 19 Oct 2010
Posts: 179
Location: India
GMAT 1: 560 Q36 V31
GPA: 3
If one root of the equation 2x^2 + 3x – k = 0 is 6, what is the value  [#permalink]

### Show Tags

17 Apr 2011, 08:17
1
1
00:00

Difficulty:

15% (low)

Question Stats:

81% (00:51) correct 19% (02:31) wrong based on 125 sessions

### HideShow timer Statistics

If one root of the equation 2x^2 + 3x – k = 0 is 6, what is the value of k?

(A) 90
(B) 42
(C) 18
(D) 10
(E) –10

_________________

petrifiedbutstanding

Retired Moderator
Joined: 16 Nov 2010
Posts: 1425
Location: United States (IN)
Concentration: Strategy, Technology
Re: If one root of the equation 2x^2 + 3x – k = 0 is 6, what is the value  [#permalink]

### Show Tags

17 Apr 2011, 08:26
Because 6 is a root, the following is true :

2* 6^2 + 3*6 - k = 0

=> k = 72 + 18 = 90

_________________

Formula of Life -> Achievement/Potential = k * Happiness (where k is a constant)

GMAT Club Premium Membership - big benefits and savings

Manager
Joined: 17 Jan 2011
Posts: 220
Re: If one root of the equation 2x^2 + 3x – k = 0 is 6, what is the value  [#permalink]

### Show Tags

17 Apr 2011, 12:33
nice,I used the roots equation
=> 6 = (-3 + sqrt(9+8K))/2*2
=> k = 90
So, A
_________________

Good Luck!!!

***Help and be helped!!!****

Manager
Joined: 03 Mar 2011
Posts: 87
Location: United States
Schools: Erasmus (S)
GMAT 1: 730 Q51 V37
GPA: 3.9

### Show Tags

05 Jul 2011, 23:47
1
We just enter this root into the equation in order to recieve an equation to find the answer!

2*6^2+3*6-k=0
k=72+18=90

_________________

If my post is useful for you not be ashamed to KUDO me!
Let kudo each other!

GMAT Tutor
Joined: 24 Jun 2008
Posts: 1325

### Show Tags

06 Jul 2011, 00:01
1
1
racejockey wrote:
If one root of the equation 2x2 + 3x – k = 0 is 6, what is the value of k?
(A) 90
(B) 42
(C) 18
(D) 10
(E) –10

The question should say that k is a constant. In that case, if 6 is a 'root' of the equation, that just means that x=6 is one solution to the equation. So we can plug in x=6:
\begin{align*} 2x^2 + 3x - k &= 0 \\ 2(6^2) + (3)(6) - k &= 0 \\ 72 + 18 &= k \\ 90 &= k \end{align*}
_________________

GMAT Tutor in Toronto

If you are looking for online GMAT math tutoring, or if you are interested in buying my advanced Quant books and problem sets, please contact me at ianstewartgmat at gmail.com

Manager
Joined: 10 Jun 2015
Posts: 118
Re: If one root of the equation 2x^2 + 3x – k = 0 is 6, what is the value  [#permalink]

### Show Tags

22 Aug 2015, 04:28
petrifiedbutstanding wrote:
If one root of the equation 2x^2 + 3x – k = 0 is 6, what is the value of k?

(A) 90
(B) 42
(C) 18
(D) 10
(E) –10

let the other root is 'a'
a +6=-3/2; a = -15/2
6a = -k/2
implies k=90
Non-Human User
Joined: 09 Sep 2013
Posts: 9157
Re: If one root of the equation 2x^2 + 3x – k = 0 is 6, what is the value  [#permalink]

### Show Tags

23 Nov 2018, 07:45
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 one root of the equation 2x^2 + 3x – k = 0 is 6, what is the value &nbs [#permalink] 23 Nov 2018, 07:45
Display posts from previous: Sort by