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

It is currently 16 Dec 2019, 03:32

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 a^2 is not equal to b^2, what is the value of a-b - a^2 - b^2

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

Hide Tags

Find Similar Topics 
Intern
Intern
avatar
B
Joined: 20 Jun 2019
Posts: 29
Location: United States (DC)
Schools: UVA Darden
GPA: 3.4
WE: Sales (Computer Software)
If a^2 is not equal to b^2, what is the value of a-b - a^2 - b^2  [#permalink]

Show Tags

New post 11 Nov 2019, 11:17
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

77% (00:51) correct 23% (01:10) wrong based on 30 sessions

HideShow timer Statistics

If \(a^2\) is not equal to \(b^2\) what is the value of \(\frac{a-b}{a^2-b^2}\)

1) a + b = 8
2) a - b = 6
Intern
Intern
avatar
B
Joined: 20 Jun 2019
Posts: 29
Location: United States (DC)
Schools: UVA Darden
GPA: 3.4
WE: Sales (Computer Software)
Re: If a^2 is not equal to b^2, what is the value of a-b - a^2 - b^2  [#permalink]

Show Tags

New post 11 Nov 2019, 11:23
According to the MGMAT answer, The question can be factored to \(\frac{a-b}{(a-b)(a+b)}\) which can be further simplified to \(\frac{1}{(a+b)}\). Can somebody walk be through how it gets simplified to \(\frac{1}{(a+b)}\)? I am getting 1+ \(\frac{a-b}{a+b}\)?

Thanks
Manhattan Prep Instructor
User avatar
G
Joined: 04 Dec 2015
Posts: 856
GMAT 1: 790 Q51 V49
GRE 1: Q170 V170
Re: If a^2 is not equal to b^2, what is the value of a-b - a^2 - b^2  [#permalink]

Show Tags

New post 11 Nov 2019, 14:20
whollymoses wrote:
According to the MGMAT answer, The question can be factored to \(\frac{a-b}{(a-b)(a+b)}\) which can be further simplified to \(\frac{1}{(a+b)}\). Can somebody walk be through how it gets simplified to \(\frac{1}{(a+b)}\)? I am getting 1+ \(\frac{a-b}{a+b}\)?

Thanks


When you simplify a fraction, you divide the entire top and the entire bottom by the same thing.

At the beginning, the top is a-b, and the bottom is (a-b)(a+b).

Divide both the top and bottom by a-b.

When you divide a-b by a-b, you get 1. (Dividing anything by itself gives you 1.)

When you divide (a-b)(a+b) by a-b, you get a+b.

So, the whole fraction, when simplified, will come out to 1/(a+b).

In shorter form:

(a-b)/(a-b)(a+b)

= ((a-b)/(a-b))/((a-b)(a+b)/(a-b))

= 1 / (a+b)
_________________
Image

Chelsey Cooley | Manhattan Prep | Seattle and Online

My latest GMAT blog posts | Suggestions for blog articles are always welcome!
Intern
Intern
avatar
B
Joined: 20 Jun 2019
Posts: 29
Location: United States (DC)
Schools: UVA Darden
GPA: 3.4
WE: Sales (Computer Software)
Re: If a^2 is not equal to b^2, what is the value of a-b - a^2 - b^2  [#permalink]

Show Tags

New post 11 Nov 2019, 14:49
ccooley wrote:
whollymoses wrote:
According to the MGMAT answer, The question can be factored to \(\frac{a-b}{(a-b)(a+b)}\) which can be further simplified to \(\frac{1}{(a+b)}\). Can somebody walk be through how it gets simplified to \(\frac{1}{(a+b)}\)? I am getting 1+ \(\frac{a-b}{a+b}\)?

Thanks


When you simplify a fraction, you divide the entire top and the entire bottom by the same thing.

At the beginning, the top is a-b, and the bottom is (a-b)(a+b).

Divide both the top and bottom by a-b.

When you divide a-b by a-b, you get 1. (Dividing anything by itself gives you 1.)

When you divide (a-b)(a+b) by a-b, you get a+b.

So, the whole fraction, when simplified, will come out to 1/(a+b).

In shorter form:

(a-b)/(a-b)(a+b)

= ((a-b)/(a-b))/((a-b)(a+b)/(a-b))

= 1 / (a+b)



Step 1) \(\frac{a-b}{(a+b)(a-b)}\)

Step 2) \(\frac{a-b}{a-b}\)* \(\frac{1}{a+b}\) . << What is the logic behind this step? Trying to understand the concept. Sorry, it's been years since I've had to do this type of math and am clearly rusty.

Step 3) \(\frac{1}{a+b}\)
GMAT Club Bot
Re: If a^2 is not equal to b^2, what is the value of a-b - a^2 - b^2   [#permalink] 11 Nov 2019, 14:49
Display posts from previous: Sort by

If a^2 is not equal to b^2, what is the value of a-b - a^2 - b^2

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





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