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If x does not equal to 0 and x = root(4xy  4y^2), then in [#permalink]
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29 Oct 2010, 23:42
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If x does not equal to 0 and \(x = \sqrt{4xy  4 y^2}\), then in terms of y, x = ? A. 2y B. y C. y/2 D. 4y^2/(14y) E. 2y
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Re: If x does not equal to 0 and x = root(4xy  4y^2), then in [#permalink]
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30 Oct 2010, 02:03
tonebeeze wrote: If x does not = 0 and \(x = \sqrt{4xy4y^2}\) , then in terms of y, x =
a. 2y b. y c. \(y/2\) d. \(4^2/14y\) e. 2y \(x = \sqrt{4xy4y^2}\) Square both sides \(x^2=4xy4y^2\) \(x^2+4y^24xy=0\) \((x2y)^2=0\) \(\Rightarrow x2y=0\) \(x=2y\) Answer : (A)
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Re: If x does not equal to 0 and x = root(4xy  4y^2), then in [#permalink]
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19 Feb 2011, 04:11
is it possible to solve this one by plugging in numbers? any help will be appreciated. thanks.
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Re: If x does not equal to 0 and x = root(4xy  4y^2), then in [#permalink]
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19 Feb 2011, 06:49
Since the question and options both involve variables, plugging the numbers is probably going to make it more complicated. Better to solve it by squaring both sides and solving for x



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Re: If x does not equal to 0 and x = root(4xy  4y^2), then in [#permalink]
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19 Feb 2011, 07:02
well, i kinda figured it out, and i think it will be good to know both systems to solve. in order to make it more simpler i will plug in Y=1 so i will have x^2=4x4 x^24x+4=0 (x2)^2=0 x=2. if u look on the answers  and plug y=1, the only one that will give u x=2 is A. therefore u have the answer very easy and quickly with almost no algebra. what do u think? thanks.
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Re: If x does not equal to 0 and x = root(4xy  4y^2), then in [#permalink]
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19 Feb 2011, 07:42
Well  even after plugging you still need to square both sides and solve for x and then you need to plug it in four choices ( which is up to five extra steps  it just so happens that in this case, only one choice is suitable). Therefore, as a general rule, I would prefer to not plug in if both question and choices have variables.



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If x does not equal to 0 and x = root(4xy  4y^2), then in [#permalink]
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21 Nov 2013, 02:06
If x does not equal to 0 and \(x = \sqrt{4xy  4 y^2}\), then in terms of y, x = ?
A. 2y B. y C. y/2 D. 4y^2/(14y) E. 2y



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Re: If x does not equal to 0 and x = root(4xy  4y^2), then in [#permalink]
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21 Nov 2013, 02:15



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Re: If x does not equal to 0 and x = root(4xy  4y^2), then in [#permalink]
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21 Nov 2013, 02:16



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Re: If x does not equal to 0 and x = root(4xy  4y^2), then in [#permalink]
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11 Jul 2015, 13:12
tonebeeze wrote: If x does not equal to 0 and \(x = \sqrt{4xy  4 y^2}\), then in terms of y, x = ?
A. 2y B. y C. y/2 D. 4y^2/(14y) E. 2y This is not a 700+ question!



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If x does not equal to 0 and x = root(4xy  4y^2), then in [#permalink]
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11 Dec 2015, 23:08
Bunuel wrote: registerincog wrote: If x does not equal to 0 and \(x = \sqrt{4xy  4 y^2}\), then in terms of y, x = ?
A. 2y B. y C. y/2 D. 4y^2/(14y) E. 2y Square the expression: \(x^2 = 4xy  4y^2\) > \(x^24xy+4y^2=(x2y)^2=0\) > \(x=2y\). Answer: A. Can you explain how you were able to get to (x2y)^2? What is the strategy to know how to determine that quickly?



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Re: If x does not equal to 0 and x = root(4xy  4y^2), then in [#permalink]
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12 Dec 2015, 08:31



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Re: If x does not equal to 0 and x = root(4xy  4y^2), then in [#permalink]
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25 Aug 2017, 11:05
tonebeeze wrote: If x does not equal to 0 and \(x = \sqrt{4xy  4 y^2}\), then in terms of y, x = ?
A. 2y B. y C. y/2 D. 4y^2/(14y) E. 2y We can square both sides of the given equation and obtain: x^2 = 4xy  4y^2 x^2  4xy + 4y^2 = 0 (x  2y)(x  2y) = 0 (x  2y)^2 = 0 x  2y = 0 x = 2y Answer: A
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