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

 It is currently 18 Jan 2019, 03:54

### 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 January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
• ### Free GMAT Strategy Webinar

January 19, 2019

January 19, 2019

07:00 AM PST

09:00 AM PST

Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.
• ### FREE Quant Workshop by e-GMAT!

January 20, 2019

January 20, 2019

07:00 AM PST

07:00 AM PST

Get personalized insights on how to achieve your Target Quant Score.

# If a^3 + a^2 – a – 1 = 0, then which one of the following could be the

Author Message
TAGS:

### Hide Tags

Manager
Joined: 26 Dec 2018
Posts: 128
Location: India
If a^3 + a^2 – a – 1 = 0, then which one of the following could be the  [#permalink]

### Show Tags

Updated on: 04 Jan 2019, 09:10
1
1
00:00

Difficulty:

5% (low)

Question Stats:

100% (00:36) correct 0% (00:00) wrong based on 16 sessions

### HideShow timer Statistics

If a^3 + a^2 – a – 1 = 0, then which one of the following could be the value of a?

(A) 0
(B) 1
(C) 2
(D) 3
(E) 4

_________________

GOOD LUCK!

Originally posted by UB001 on 04 Jan 2019, 09:06.
Last edited by Bunuel on 04 Jan 2019, 09:10, edited 1 time in total.
Renamed the topic.
Manager
Joined: 09 Mar 2018
Posts: 196
Location: India
If a^3 + a^2 – a – 1 = 0, then which one of the following could be the  [#permalink]

### Show Tags

Updated on: 04 Jan 2019, 11:02
1
Manipulating the question to give

$$a^3 + a^2 – a – 1 = 0$$
$$a^2(a + 1) – 1(a + 1) = 0$$
$$(a^2 -1) (a + 1) = 0$$
$$a^2 = 1$$ or a = -1

So as you can see there are no -ive values present in the answer options.

_________________

If you notice any discrepancy in my reasoning, please let me know. Lets improve together.

Quote which i can relate to.
Many of life's failures happen with people who do not realize how close they were to success when they gave up.

Originally posted by KanishkM on 04 Jan 2019, 10:05.
Last edited by KanishkM on 04 Jan 2019, 11:02, edited 1 time in total.
GMATH Teacher
Status: GMATH founder
Joined: 12 Oct 2010
Posts: 616
Re: If a^3 + a^2 – a – 1 = 0, then which one of the following could be the  [#permalink]

### Show Tags

04 Jan 2019, 11:00
UB001 wrote:
If a^3 + a^2 – a – 1 = 0, then which one of the following could be the value of a?

(A) 0
(B) 1
(C) 2
(D) 3
(E) 4

$${a^3} + {a^2} = a + 1$$

$$?\,\,\,:\,\,\,{\rm{could}}\,\,{\rm{be}}\,\,a$$

Let´s do a trivial alternatives INSPECTION:

$$\left( A \right)\,\,0\mathop = \limits^? 1\,\,\,{\rm{no}}$$

$$\left( B \right)\,\,2\mathop = \limits^? 2\,\,\,{\rm{yes}}\,\,\,\,\,\,\,\, \Rightarrow \,\,\,\,? = 1\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,\left( {\rm{B}} \right)$$

Regards,
Fabio.
_________________

Fabio Skilnik :: GMATH method creator (Math for the GMAT)
Our high-level "quant" preparation starts here: https://gmath.net

Re: If a^3 + a^2 – a – 1 = 0, then which one of the following could be the &nbs [#permalink] 04 Jan 2019, 11:00
Display posts from previous: Sort by