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nervesofsteel
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square both sides: 8xy - 16y^2 = x^2
so x^2 - 8xy + 16y^2 = 0
(x-4y)(x-4y) = 0
x = 4y.
(D)
X = ?
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tohellandback
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I don't understand this..whats wrong with the following
x = sqrt(8xy-16y^2)
we know that x=0
putting x=0 and squaring both sides
16y^=0
y=0
so it can be any of the options.
where did you get the question from?
x = sqrt(8xy-16y^2)
we know that x=0
putting x=0 and squaring both sides
16y^=0
y=0
so it can be any of the options.
where did you get the question from?
The powers of two are bloody impolite!!
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ssmiles08
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silly me...I always seem to rush pass the questions. you are right. y = 0. Something with the question is wrongly worded. Are you sure it said x =0? or maybe it said x =/= 0 instead?tohellandback wrote: we know that x=0
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nervesofsteel
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nervesofsteel
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ssmiles08 wrote:square both sides: 8xy - 16y^2 = x^2
so x^2 - 8xy + 16y^2 = 0
(x-4y)(x-4y) = 0
x = 4y.
(D)
I think this is the right approach...
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tohellandback
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My goal here is not to match the OA because I am sure this exact question is not going to be there on the test.nervesofsteel wrote:ssmiles08 wrote:square both sides: 8xy - 16y^2 = x^2
so x^2 - 8xy + 16y^2 = 0
(x-4y)(x-4y) = 0
x = 4y.
(D)
I think this is the right approach...
now even if you agree to
x=4y, or y=x/4
since x=0, y=0.
or, x=– 4y
or x=4y
or x=y
or x=4y
or x=4y^2
so where is this wrong
The powers of two are bloody impolite!!
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mikeCoolBoy
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since x = 0 and x = sqrt(8xy-16y^2)
substituting x = 0 ---> 0 = sqrt(-16y^2) that I believe can only be true if y = 0 making C the correct answer.
So I agree with ssmiles08 and tohellandback that something is wrong with the question.
substituting x = 0 ---> 0 = sqrt(-16y^2) that I believe can only be true if y = 0 making C the correct answer.
So I agree with ssmiles08 and tohellandback that something is wrong with the question.
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gmatplayer
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