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What is the value of x^2 − y^2 ? (1) (x - y)^2 = 9 (2) x + y = 6

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P
Joined: 01 Sep 2010
Posts: 3304
What is the value of x^2 − y^2 ? (1) (x - y)^2 = 9 (2) x + y = 6  [#permalink]

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New post 27 Jul 2017, 08:09
3
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E

Difficulty:

  25% (medium)

Question Stats:

73% (01:16) correct 27% (01:25) wrong based on 352 sessions

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Posts: 6961
Re: What is the value of x^2 − y^2 ? (1) (x - y)^2 = 9 (2) x + y = 6  [#permalink]

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New post 27 Jul 2017, 09:14
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1
carcass wrote:
What is the value of \(x^2 - y^2\) ?


(1) \((x - y)^2 = 9\)

(2) x + y = 6




\(x^2-y^2=(x+y)(x-y)\)

STATEMENTS..

(1) \((x - y)^2 = 9\)
x-y= 3..
x-y=-3..
various combinations of x and y possible fitting in any of two above
insuff

(2) x + y = 6
we do not know what is x-y
insuff

combined..
we know x+y=6..
but x-y can be 3, then ans is 18
OR x-y can be -3 ans will be -18

insuff

E
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Re: What is the value of x^2 − y^2 ? (1) (x - y)^2 = 9 (2) x + y = 6  [#permalink]

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New post 06 Aug 2017, 07:50
1
lets consider both case 1 and 2

x=6-y

(6-y-y)^2=9
6-2y=3 or -3
we can have two values of y and x

so, not sufficient

e
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Re: What is the value of x^2 − y^2 ? (1) (x - y)^2 = 9 (2) x + y = 6  [#permalink]

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New post 31 Jul 2018, 08:03
What is the value of \(x^2 - y^2\)?

(1) \((x-y)^2=9\)
(2) \(x+y=6\)
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Re: What is the value of x^2 − y^2 ? (1) (x - y)^2 = 9 (2) x + y = 6  [#permalink]

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New post 31 Jul 2018, 08:11
throw123 wrote:
What is the value of \(x^2 - y^2\)?

(1) \((x-y)^2=9\)
(2) \(x+y=6\)



\(x^2 - y^2 = (x+y) (x - y)\)

Statement 1 :

\((x-y)^2 = 9\)

x - y = +3 or -3

At the same time we don't know about x-y

NOT sufficient.

Statement 2 :

x + y = 6.

No information regarding x - y .Not sufficient.

1+ 2:

As we have 2 values for x - y , it's not possible to find out any specific value of \(x^2 - y^2\)

The best answer is E.
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Re: What is the value of x^2 − y^2 ? (1) (x - y)^2 = 9 (2) x + y = 6  [#permalink]

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New post 31 Jul 2018, 09:41
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Re: What is the value of x^2 − y^2 ? (1) (x - y)^2 = 9 (2) x + y = 6 &nbs [#permalink] 31 Jul 2018, 09:41
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