Respuesta :

-2y + 2

Explanation

We have (x - y + 1) - (x + y - 1)

Let’s expand the Parentheses

= x - y + 1 - x - y + 1

Then let’s group the like terms

= (x - x) + (- y - y) + (1 + 1)

= 0 - 2y + 2

= 2y + 2