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... ...

If Image and x and y are integers, then which one of the following must be true?
(A)    x is divisible by 4
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Nova Math - Problem Set F: Number Theory

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Posted: 05/16/2012 02:55
How can you solve this with x and y at the end?
Arcadia
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Posted: 05/16/2012 09:56
First, we reduce the equation to
x + y = 3x - 3y
2x - 4y =0
x - 2y = 0
x = 2y
or, y = x/2

Since x and y are integers:
x must be an even number, since it is always a multiple of 2

That's about the only thing we can conclude.


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Posted: 07/15/2012 17:11
Wouldn't this also force y to be an odd number as well?
Arcadia
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Posted: 07/18/2012 18:46
Hi Cef Usa. No, it won't force y to be an odd number. y can be = 2, for example, for x = 4.
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