Question

Simplify (x - y + 1) - (x + y - 1)

Answer 1

First, distribute the minus sign across the second set. So you have:

x - y + 1 - x - y + 1

Now, we combine like terms:
x-x=0
-y-y=-2y
1+1=2

So we have -2y+2

Hope that helps.