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