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Re: If (x – y)3 > (x – y)2, then which one of the following must [#permalink]
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tavishg wrote:
Hi Carcass
How do I prove C and D wrong?


That's is a very good question.

I think you are thinking to pick up numbers and test the answer choices. Working on them which is true and which is not. I understood what you mean. However, the best way is to manipulate the stem and thinking logically

Now, \((x – y)^3 > (x – y)^2\)

the LHS is positive because squared

So we can divide both for the LHS and we will end up with

x-y>1

x > 1+y

So x is > of y (some number) +1

So x>y and ONLY x^3>y^3

The other options such as D could not be true or yes

Proving C and D are wrong is too cumbersome in a classic way

I hope I satisfied your question
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Re: If (x – y)3 > (x – y)2, then which one of the following must [#permalink]
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This is really confusing.
We assume that x & y are negative
x=-2 and y=-4
(-2-(-4)^3> (-2-(-4)^2
in this case only E fits here
(E) x^3 > y^3
(-2)^3 > (-4)^3
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Re: If (x y)3 > (x y)2, then which one of the following must [#permalink]
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Re: If (x y)3 > (x y)2, then which one of the following must [#permalink]
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