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Source: — Data Sufficiency |
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by real2008 » Tue Jul 28, 2009 5:39 pm
6xy = x^2y + 9y

=> y is either 0 or x is 3

1) if x=-2, then y is zero, hence xy=0
2) if x<0, then again y is zero, hence xy=0

so D.
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by under_net » Tue Jul 28, 2009 6:59 pm
@Real2008

Can you please explain how did u simplify the equation.
Did u assume values to get to X = 3 and Y= 0
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by gmat_2010 » Fri Jul 31, 2009 2:32 am
I am guessing he has assumed x^2y as (x^2)y. I assumed it as x^(2y). If it is (x^2)y then he is correct.
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by tohellandback » Fri Jul 31, 2009 2:40 am
IMO D

6xy = x^2y + 9y
y(x^2-6x+9)=0
y(x-3)^2=0
y=0 or x=3

1) x = –2 , so Y must be 0, xy=0
sufficient

2) x<0, again y must be 0,xy=0
sufficient
The powers of two are bloody impolite!!
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