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For such algebra questions, please substitute answer options. In this question, please notice that all the answer options are possible values of integer y.
Rearrange the equation, 2y - x = 2xy
x = 2y/(2y + 1)

We know x and y are both Integers and x ≠ 0.

Now substitute values of y from the answer options, to check which of them provides integer value of x.

A. y= 2, then x = 4/5 Not Integer
(B) y = 1, then x = 2/3 Not Integer
(C) y = 0, then x = 0 Not Possible since x ≠ 0
(D) y = -1, then x = 2 Integer
(E) y = - 2, then x = 4/3 Not Integer

Hence, the correct answer is Option D. -1
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HanktheTank
2y - x = 2xy and x ≠ 0. If x and y are integers, which of the following could equal y?

(A) 2
(B) 1
(C) 0
(D) -1
(E) - 2

I understand how to get to the answer (D) but I can't figure out how to simplify the equation and feel like I am missing something. anyone know how to simplify 2y - x = 2xy into x in terms of y and can explain the steps? Thanks!

The key point here is to get every term that has a x in it on the same side. (If you want x in terms of y, put all of the xs on the same side. If you want y in terms of x, put all of the ys on the same side.)

It looks like this:

2y - x = 2xy
2y = 2xy + x
2y = x(2y + 1) (this is the most important step - since we have all of the xs together on one side, we can 'pull out' an x...)
x = 2y / (2y + 1)

And there's your simplified equation!
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