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

 It is currently 19 Jun 2019, 18:06

### 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

# How many roots does the equation (x^2-1)/(x+1)=x have?

Author Message
TAGS:

### Hide Tags

Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 7471
GMAT 1: 760 Q51 V42
GPA: 3.82
How many roots does the equation (x^2-1)/(x+1)=x have?  [#permalink]

### Show Tags

24 May 2019, 02:20
1
2
00:00

Difficulty:

45% (medium)

Question Stats:

48% (00:52) correct 52% (00:54) wrong based on 69 sessions

### HideShow timer Statistics

[GMAT math practice question]

How many roots does the equation $$\frac{(x^2-1)}{(x+1)}=x$$ have?

$$A. 0$$

$$B. 1$$

$$C. 2$$

$$D. 3$$

$$E. 4$$

_________________
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 $149 for 3 month Online Course" "Free Resources-30 day online access & Diagnostic Test" "Unlimited Access to over 120 free video lessons - try it yourself" Intern Joined: 22 Jan 2019 Posts: 3 Re: How many roots does the equation (x^2-1)/(x+1)=x have? [#permalink] ### Show Tags 24 May 2019, 02:32 X is never equal to X-1 so, zero roots. Posted from my mobile device CEO Joined: 18 Aug 2017 Posts: 3893 Location: India Concentration: Sustainability, Marketing GPA: 4 WE: Marketing (Energy and Utilities) Re: How many roots does the equation (x^2-1)/(x+1)=x have? [#permalink] ### Show Tags 24 May 2019, 09:28 MathRevolution wrote: [GMAT math practice question] How many roots does the equation $$\frac{(x^2-1)}{(x+1)}=x$$ have? $$A. 0$$ $$B. 1$$ $$C. 2$$ $$D. 3$$ $$E. 4$$ solve for $$\frac{(x^2-1)}{(x+1)}=x$$ we get x-1=x x=0 roots IMO A _________________ If you liked my solution then please give Kudos. Kudos encourage active discussions. Math Revolution GMAT Instructor Joined: 16 Aug 2015 Posts: 7471 GMAT 1: 760 Q51 V42 GPA: 3.82 Re: How many roots does the equation (x^2-1)/(x+1)=x have? [#permalink] ### Show Tags 26 May 2019, 18:58 => $$\frac{(x^2-1)}{(x+1)}=x$$ $$=> \frac{(x+1)(x-1)}{(x+1)} = x$$ $$=> x-1 = x$$ by canceling $$(x+1).$$ But $$x – 1 = x$$ has no solution. Therefore, the answer is A. Answer: A _________________ 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$149 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"
ISB School Moderator
Joined: 08 Dec 2013
Posts: 432
Location: India
Concentration: Nonprofit, Sustainability
GMAT 1: 630 Q47 V30
WE: Operations (Non-Profit and Government)
Re: How many roots does the equation (x^2-1)/(x+1)=x have?  [#permalink]

### Show Tags

26 May 2019, 19:02
MathRevolution wrote:
[GMAT math practice question]

How many roots does the equation $$\frac{(x^2-1)}{(x+1)}=x$$ have?

$$A. 0$$

$$B. 1$$

$$C. 2$$

$$D. 3$$

$$E. 4$$

Cross multiply:- x^2 -1 = x^2 + x
x= -1, one root but not possible as it'll render the LHS infinity. So zero root. (A)
_________________
Kindly drop a '+1 Kudos' if you find this post helpful.

GMAT Math Book

-I never wanted what I gave up
I never gave up what I wanted-
Manager
Joined: 01 Jan 2018
Posts: 156
Re: How many roots does the equation (x^2-1)/(x+1)=x have?  [#permalink]

### Show Tags

03 Jun 2019, 12:35
LeoN88 wrote:
MathRevolution wrote:
[GMAT math practice question]

How many roots does the equation $$\frac{(x^2-1)}{(x+1)}=x$$ have?

$$A. 0$$

$$B. 1$$

$$C. 2$$

$$D. 3$$

$$E. 4$$

Cross multiply:- x^2 -1 = x^2 + x
x= -1, one root but not possible as it'll render the LHS infinity. So zero root. (A)

LeoN88,
Can you please explain the portion marked by green-

Cross multiply:- x^2 -1 = x^2 + x
x= -1, one root but not possible as it'll render the LHS infinity. So zero root.

_________________
kudos please if it helped you.
ISB School Moderator
Joined: 08 Dec 2013
Posts: 432
Location: India
Concentration: Nonprofit, Sustainability
GMAT 1: 630 Q47 V30
WE: Operations (Non-Profit and Government)
Re: How many roots does the equation (x^2-1)/(x+1)=x have?  [#permalink]

### Show Tags

03 Jun 2019, 17:28
1
tamal99 wrote:
LeoN88 wrote:
MathRevolution wrote:
[GMAT math practice question]

How many roots does the equation $$\frac{(x^2-1)}{(x+1)}=x$$ have?

$$A. 0$$

$$B. 1$$

$$C. 2$$

$$D. 3$$

$$E. 4$$

Cross multiply:- x^2 -1 = x^2 + x
x= -1, one root but not possible as it'll render the LHS infinity. So zero root. (A)

LeoN88,
Can you please explain the portion marked by green-

Cross multiply:- x^2 -1 = x^2 + x
x= -1, one root but not possible as it'll render the LHS infinity. So zero root.

tamal99

If I put x=-1 in the equation stem the denominator of the fraction will become infinity so not possible.

(x^2 -1 )/(x+1) so x!= -1
_________________
Kindly drop a '+1 Kudos' if you find this post helpful.

GMAT Math Book

-I never wanted what I gave up
I never gave up what I wanted-
Manager
Joined: 25 Mar 2018
Posts: 65
Location: India
Schools: ISB '21, IIMA , IIMB
GMAT 1: 650 Q50 V28
GPA: 4
WE: Analyst (Manufacturing)
Re: How many roots does the equation (x^2-1)/(x+1)=x have?  [#permalink]

### Show Tags

03 Jun 2019, 17:37
MathRevolution wrote:
[GMAT math practice question]

How many roots does the equation $$\frac{(x^2-1)}{(x+1)}=x$$ have?

$$A. 0$$

$$B. 1$$

$$C. 2$$

$$D. 3$$

$$E. 4$$

On solving the equation we get x = -1. But x = -1 cannot be the root. So we have 0 roots. So option A is correct

Posted from my mobile device
_________________
Please give me +1 kudos if my post helps you a little. It will help me unlock tests. Thanks
Re: How many roots does the equation (x^2-1)/(x+1)=x have?   [#permalink] 03 Jun 2019, 17:37
Display posts from previous: Sort by