“y in terms of x”: Can I move the variables around since we're dealing with addition and subtraction?

Question

Can I move the variables around since we're dealing with addition and subtraction?

Answer

You can always change the order of the terms in an expression as long as you keep the sign:

Let's look at:

a - b + 3c - 2d - e

I could rearrange this to:

-2d - b + 3c + a - e or:

-e - b - 2d + a + 3c or:

3c + a - e - b - 2d or many more ways. Just remember the sign "-" or "+" in front of every term should be the same.

Link

http://gre.magoosh.com/questions/145