GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

 It is currently 27 Jan 2020, 14:22

### 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 a - b ? (1) a^2 - b^2 = 9 (2) a^2 - 2ab + b^2 = 1

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 60687
What is the value of a - b ? (1) a^2 - b^2 = 9 (2) a^2 - 2ab + b^2 = 1  [#permalink]

### Show Tags

13 Nov 2019, 01:56
00:00

Difficulty:

55% (hard)

Question Stats:

54% (01:44) correct 46% (01:21) wrong based on 52 sessions

### HideShow timer Statistics

What is the value of (a - b) ?

(1) $$a^2 - b^2=9$$

(2) $$a^2-2ab+b^2=1$$

Are You Up For the Challenge: 700 Level Questions

_________________
Math Expert
Joined: 02 Aug 2009
Posts: 8332
Re: What is the value of a - b ? (1) a^2 - b^2 = 9 (2) a^2 - 2ab + b^2 = 1  [#permalink]

### Show Tags

13 Nov 2019, 02:10
What is the value of (a - b) ?

(1) $$a^2 - b^2=9$$
(a-b)(a+b)=9... a-b could be anything 1,9,1/9,-1,

(2) $$a^2-2ab+b^2=1.......(a-b)^2=1......a-b=1..or ..a-b=-1$$

Combined
a-b=1...a+b=9
a-b=-1..a+b=-9
Insufficient

E

Note a and b could be anything — positive or negative, integer or fraction
_________________
Re: What is the value of a - b ? (1) a^2 - b^2 = 9 (2) a^2 - 2ab + b^2 = 1   [#permalink] 13 Nov 2019, 02:10
Display posts from previous: Sort by