Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 04 May 2015, 18:18

### 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 June
Open Detailed Calendar

# Ds - 1000Q

Author Message
TAGS:
Director
Joined: 05 Feb 2006
Posts: 902
Followers: 1

Kudos [?]: 51 [0], given: 0

Ds - 1000Q [#permalink]  16 Nov 2006, 10:56
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
Is sqrt((x-3)^2)=3-x

1) x not equal to 3
2) -xlxl>0

Director
Joined: 12 Jun 2006
Posts: 536
Followers: 1

Kudos [?]: 29 [0], given: 1

A

1) (x-3)^2 = 3-x
2) x^2 - 6x + 9 = 3-x
3) x^2 + 9 = 3 + 5x
4) x^2 + 6 = 5x
5) x^2 - 5x + 6 = 0
6) x=2 and 3

Statement 1 says x doesn't equal 3. That leaves 2.

Statement 2 tells us that x is positive. That could be 2 or 3.

Is this right?
Director
Joined: 05 Feb 2006
Posts: 902
Followers: 1

Kudos [?]: 51 [0], given: 0

ggarr wrote:
A

1) (x-3)^2 = 3-x
2) x^2 - 6x + 9 = 3-x
3) x^2 + 9 = 3 + 5x
4) x^2 + 6 = 5x
5) x^2 - 5x + 6 = 0
6) x=2 and 3

Statement 1 says x doesn't equal 3. That leaves 2.

Statement 2 tells us that x is positive. That could be 2 or 3.

Is this right?

Nope.

You forgot to raise (3-x)^2.....
VP
Joined: 15 Jul 2004
Posts: 1473
Schools: Wharton (R2 - submitted); HBS (R2 - submitted); IIMA (admitted for 1 year PGPX)
Followers: 17

Kudos [?]: 116 [0], given: 13

Re: Ds - 1000Q [#permalink]  16 Nov 2006, 11:54
SimaQ wrote:
Is sqrt((x-3)^2)=3-x

1) x not equal to 3
2) -xlxl>0

Going with B - stmt 2 alone is sufficient but 1 is not.

since -x|x| >0 ==> x < 0.

This means x - 3 < 0 and therefore we know that x - 3 is a negative number that is being squared. when you take the sqr root of the square of a negative number we should consider the negative root as the result.

sqrt(-3^2) = -3

Thus sqrt((x-3)^2) = - (x - 3) = 3-x

What do you think??
Intern
Joined: 11 Sep 2006
Posts: 44
Followers: 0

Kudos [?]: 3 [0], given: 0

My answer is D. From the stem we get:

(x-3)^2=(3-x)^2

Plug in any values for x and they are equal. It seems that you can solve this from the info. in the stem, is that right?
Director
Joined: 12 Jun 2006
Posts: 536
Followers: 1

Kudos [?]: 29 [0], given: 1

Don't the 2 equations equal one another? If so, wouldn't the answer be D?
Senior Manager
Joined: 20 Feb 2006
Posts: 373
Followers: 1

Kudos [?]: 2 [0], given: 0

I'm puzzled by this one - as mentioned, the stem gives an equivalent equation
Director
Joined: 11 Sep 2006
Posts: 514
Followers: 2

Kudos [?]: 35 [0], given: 0

Maybe I'm really far off on this one, but...
the square root of (x-3)^2...isn't that just (x-3)? So isn't the question asking, is x-3 = 3-x? And if you solve the equation, then the stem is just, is x = 3? If that's the case, then only A is correct...
What is OA?
_________________

...there ain't no such thing as a free lunch...

Intern
Joined: 11 Nov 2006
Posts: 16
Followers: 0

Kudos [?]: 1 [0], given: 0

From-1 : we get (x-3) or 3-x
From-2 : x < 0 means x-3 must be negative which when sqared.
on sqare-rooting it should give us 3 - x.

so Stmt-2 alone is sufficient..

B
_________________

Regards,
Ahamdevam

GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5078
Location: Singapore
Followers: 22

Kudos [?]: 184 [0], given: 0

St1:

x = 2, sqrt((x-3)^2) = 1, 3-x = 1 --> LHS = RHS
x = 7, sqrt((x-3)^2) = 4, 3-7 = -4 --> LSH != RHS

Insufficient.

St2:

|x| is alway positive, so x must be negative for -x|x| to be positive.

x = -1, sqrt((x-3)^2) = 4, 3-x = 4 --> LHS = RHS
x = -2, sqrt((x-3)^2) = 5, 3-x = 5 --> LHS = RHS
x = -7, sqrt((x-3)^2) = 10, 3-x = 10 --> LHS = RHS
x = -1/2, sqrt((x-3)^2) = 3.5, x-x = 3.5 --> LHS = RHS

I'll take B.
VP
Joined: 28 Mar 2006
Posts: 1384
Followers: 2

Kudos [?]: 19 [0], given: 0

Re: Ds - 1000Q [#permalink]  16 Nov 2006, 18:46
SimaQ wrote:
Is sqrt((x-3)^2)=3-x

1) x not equal to 3
2) -xlxl>0

Straight B....

-x|x| > 0 if x is -ve.

|x| is always positive

for -x|x| > 0 then x has to be -ve.

1) Isnt needed

\\So B
Director
Joined: 05 Feb 2006
Posts: 902
Followers: 1

Kudos [?]: 51 [0], given: 0

OA is B.

I needed the clearence on -xlxl>0 part....
Intern
Joined: 11 Sep 2006
Posts: 44
Followers: 0

Kudos [?]: 3 [0], given: 0

I think I'm mixed up with simplifying. Can somebody explain why
sqrt((x-3)^2)=3-x isn't the same as (x-3)^2=(3-x)^2 ?
VP
Joined: 15 Jul 2004
Posts: 1473
Schools: Wharton (R2 - submitted); HBS (R2 - submitted); IIMA (admitted for 1 year PGPX)
Followers: 17

Kudos [?]: 116 [0], given: 13

Googlore wrote:
I think I'm mixed up with simplifying. Can somebody explain why
sqrt((x-3)^2)=3-x isn't the same as (x-3)^2=(3-x)^2 ?

(x-3)^2=(3-x)^2 are equal. But the if squares of two numbers are equal doesn't mean that the numbers too are equal. They could be opposite in sign and still their squares would be the same.
Similar topics Replies Last post
Similar
Topics:
SC 1000 Q1~5 1 19 Sep 2007, 17:10
PS - 1000Q 2 05 Nov 2006, 10:08
Ds - 1000Q 4 16 Oct 2006, 11:39
ds 6 08 May 2005, 05:44
ds: 6 08 May 2005, 05:42
Display posts from previous: Sort by