x and y equlity question

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x and y equlity question

by r_walid » Thu Oct 29, 2009 11:41 pm
if xy different than 0.

x^2y2 - (xy) = 6, which of the following can be y in terms of x

I- 1/(2x)
II- -2/x
III- 3/x


A- I only
B- II only
C- I & II
D- I and III
E- II and III

please describe your reasoning.

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by jaspreet_takhar » Fri Oct 30, 2009 1:52 am
x^2y^2 - xy = 6
i:e x^2y^2 - xy - 6 = 0
(xy)^2 - xy - 6 =0
(xy-3)(xy+2)= 0

when xy- 3 = 0, then y = 3/x
when xy + 2 = 0, then y= -2/x

So, ans - E