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

 It is currently 07 Dec 2019, 11:41

### 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

# What is the value of y-x^2-x?

Author Message
TAGS:

### Hide Tags

Manager
Status: Never ever give up on yourself.Period.
Joined: 23 Aug 2012
Posts: 130
Location: India
Concentration: Finance, Human Resources
GMAT 1: 570 Q47 V21
GMAT 2: 690 Q50 V33
GPA: 3.5
WE: Information Technology (Investment Banking)
What is the value of y-x^2-x?  [#permalink]

### Show Tags

06 Jan 2013, 08:09
2
00:00

Difficulty:

45% (medium)

Question Stats:

66% (01:45) correct 34% (01:42) wrong based on 228 sessions

### HideShow timer Statistics

What is the value of y-x^2-x?

(1) y = -3x
(2) y = -4(x + 1)

_________________
Don't give up on yourself ever. Period.
Beat it, no one wants to be defeated (My journey from 570 to 690) : http://gmatclub.com/forum/beat-it-no-one-wants-to-be-defeated-journey-570-to-149968.html
Manager
Joined: 06 May 2012
Posts: 60
Location: India
Concentration: General Management, Finance
GMAT 1: 670 Q48 V34
GMAT 2: 720 Q49 V40
Re: What is the value of y-x^2-x?  [#permalink]

### Show Tags

06 Jan 2013, 08:55
4
We need to find whether info is sufficient to find value of y-x2-x.

We cant simplify the question stem further, so lets start with st1:
(1) y = -3x --> two vars 1 eq--> cant solve
(2) y = -4(x + 1) --> two vars 1 eq--> cant solve

1+2 together is solvable.
y=-3x and also y=-4x-4

so -3x=-4x-4
x=-4, y=12
we dont actually need to solve but for illustration i did. Knowing that we can solve them to get unique values of x and y is enough.

So 1 and 2 taken together are sufficient

Best Regards,
Mansoor

Manager
Joined: 12 Jan 2013
Posts: 142
Re: What is the value of y-x^2-x?  [#permalink]

### Show Tags

18 Jul 2013, 14:17
Can someone please give a more in depth explanation to this. I would also appreciate if the question was $$using markup$$ because the expression in the question above is rather ambiguous.
Math Expert
Joined: 02 Sep 2009
Posts: 59588
Re: What is the value of y-x^2-x?  [#permalink]

### Show Tags

18 Jul 2013, 14:24
1
aeglorre wrote:
Can someone please give a more in depth explanation to this. I would also appreciate if the question was $$using markup$$ because the expression in the question above is rather ambiguous.

What is the value of $$y-x^2-x$$?

(1) y = -3x --> the question becomes: what is the value of $$-3x-x^2-x$$. We need the value of x to answer this question. Not sufficient.

(2) y = -4(x + 1) --> the question becomes: what is the value of $$-4(x + 1)-x^2-x$$. We need the value of x to answer this question. Not sufficient.

(1)+(2) We have two distinct linear equations: $$y = -3x$$ and $$y = -4(x + 1)$$, thus we can solve for both variables and get the value of $$y-x^2-x$$. Sufficient.

Hope it's clear.
_________________
Manager
Joined: 12 Jan 2013
Posts: 142
Re: What is the value of y-x^2-x?  [#permalink]

### Show Tags

18 Jul 2013, 22:12
Awesome, thanks a lot Bunuel. You are, as they say, "The Man".

Posted from my mobile device
Manager
Joined: 11 Sep 2013
Posts: 131
Concentration: Finance, Finance
Re: What is the value of y-x^2-x?  [#permalink]

### Show Tags

24 Oct 2013, 13:24
The explanation about linear equation is not clear
Math Expert
Joined: 02 Sep 2009
Posts: 59588
Re: What is the value of y-x^2-x?  [#permalink]

### Show Tags

25 Oct 2013, 02:04
Raihanuddin wrote:
The explanation about linear equation is not clear

If you have n distinct linear equations and n variables then you can solve for them. "Distinct linear equations" means that no equation can be derived with the help of others or by arithmetic operation (by multiplication, addition, ...).

We have two distinct linear equations: $$y = -3x$$ and $$y = -4(x + 1)$$. Solving gives: x=-4 and y=12.

Hope it's clear.
_________________
EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 15661
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: What is the value of y-x^2-x?  [#permalink]

### Show Tags

21 May 2015, 11:49
Hi All,

This DS question can be solved with a combination of TESTing VALUES and Algebra skills.

We're asked for the value of Y - X^2 - X.

Fact 1: Y = -3X

IF....
X = 0
Y = 0
The answer to the question is 0 - 0^2 - 0 = 0

IF...
X = 1
Y = -3
The answer to the question is -3 - 1^2 - 1 = -5
Fact 1 is INSUFFICIENT

Fact 2: Y = -4(X+1)

IF...
X = 0
Y = -4
The answer to the question is -4 - 0^2 - 0 = -4

IF...
X = 1
Y = -8
The answer to the question is -8 - 1^2 - 1 = -10
Fact 2 is INSUFFICIENT

Combined, we know...
Y = -3X
Y = -4(X+1)

Looking at this, you should recognize a "system" of equations - we can set the equations equal to one another...

-3X = -4X - 4
X = -4

With one fixed value for X, we can solve for Y:

Y = -3(-4) = 12

Thus, X = -4 and Y = 12, so we CAN answer the question.
Combined, SUFFICIENT

GMAT assassins aren't born, they're made,
Rich
_________________
Contact Rich at: Rich.C@empowergmat.com

The Course Used By GMAT Club Moderators To Earn 750+

souvik101990 Score: 760 Q50 V42 ★★★★★
ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★
Manager
Joined: 26 Apr 2015
Posts: 123
Re: What is the value of y-x^2-x?  [#permalink]

### Show Tags

24 May 2015, 00:03
Bunuel wrote:
aeglorre wrote:
Can someone please give a more in depth explanation to this. I would also appreciate if the question was $$using markup$$ because the expression in the question above is rather ambiguous.

What is the value of $$y-x^2-x$$?

(1) y = -3x --> the question becomes: what is the value of $$-3x-x^2-x$$. We need the value of x to answer this question. Not sufficient.

(2) y = -4(x + 1) --> the question becomes: what is the value of $$-4(x + 1)-x^2-x$$. We need the value of x to answer this question. Not sufficient.

(1)+(2) We have two distinct linear equations: $$y = -3x$$ and $$y = -4(x + 1)$$, thus we can solve for both variables and get the value of $$y-x^2-x$$. Sufficient.

Hope it's clear.

Does this question belongs to the 700 level category? Seems pretty straightforward for a 700 leveler...
Math Expert
Joined: 02 Sep 2009
Posts: 59588
Re: What is the value of y-x^2-x?  [#permalink]

### Show Tags

24 May 2015, 06:56
Bunuel wrote:
aeglorre wrote:
Can someone please give a more in depth explanation to this. I would also appreciate if the question was $$using markup$$ because the expression in the question above is rather ambiguous.

What is the value of $$y-x^2-x$$?

(1) y = -3x --> the question becomes: what is the value of $$-3x-x^2-x$$. We need the value of x to answer this question. Not sufficient.

(2) y = -4(x + 1) --> the question becomes: what is the value of $$-4(x + 1)-x^2-x$$. We need the value of x to answer this question. Not sufficient.

(1)+(2) We have two distinct linear equations: $$y = -3x$$ and $$y = -4(x + 1)$$, thus we can solve for both variables and get the value of $$y-x^2-x$$. Sufficient.

Hope it's clear.

Does this question belongs to the 700 level category? Seems pretty straightforward for a 700 leveler...

The difficulty level is based on user attempts on this question. Check the stats in the original post.
_________________
EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 15661
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: What is the value of y-x^2-x?  [#permalink]

### Show Tags

24 May 2015, 10:47

As you study, you're going to find that what you think is "hard" is not necessarily what the Test Makers 'define' as "hard" (and vice-versa). It's not practical to spend time trying to assess the difficulty level of any individual question. Since your goal is almost certainly to increase your scores, you should look at the types of questions that you're getting wrong and WHY you're getting them wrong. If you get a question wrong that you SHOULD have gotten correct (but you made a silly/little mistake), then I don't care what 'level' of question it is - you've got to work to keep those mistakes from happening (since too many little mistakes will kill your scores).

GMAT assassins aren't born, they're made,
Rich
_________________
Contact Rich at: Rich.C@empowergmat.com

The Course Used By GMAT Club Moderators To Earn 750+

souvik101990 Score: 760 Q50 V42 ★★★★★
ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★
Non-Human User
Joined: 09 Sep 2013
Posts: 13725
Re: What is the value of y-x^2-x?  [#permalink]

### Show Tags

06 Aug 2019, 20:24
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: What is the value of y-x^2-x?   [#permalink] 06 Aug 2019, 20:24
Display posts from previous: Sort by