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# If R=1+2xy+(x^2)(y^2), what is the value of xy? (1) R=0 (2)

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Joined: 17 Dec 2007
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If R=1+2xy+(x^2)(y^2), what is the value of xy? (1) R=0 (2) [#permalink]

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19 Dec 2007, 12:56
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

If R=1+2xy+(x^2)(y^2), what is the value of xy?

(1) R=0
(2) x>0

Kudos [?]: 17 [0], given: 0

CEO
Joined: 17 Nov 2007
Posts: 3584

Kudos [?]: 4583 [0], given: 360

Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40

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19 Dec 2007, 13:36
A

R=1+2xy+x²y²=(1+xy)²

(1) R=0: (1+xy)²=0 ==> xy=-1. suff.
(2) x>0: insuff.

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CEO
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19 Dec 2007, 13:54
mbsnyc wrote:
If R=1+2xy+(x^2)(y^2), what is the value of xy?

(1) R=0
(2) x>0

x^2y^2+2xy+1 --> (xy+1)(xy+1)=R if we know r wel know xy.

1) suff. xy=-1

2) nothing.

A

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Senior Manager
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19 Dec 2007, 13:58
A for the reasons above.

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19 Dec 2007, 13:58
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# If R=1+2xy+(x^2)(y^2), what is the value of xy? (1) R=0 (2)

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