Rat'l Expression: (x^2-y^2-4x+4y)/(x^2-y^2+4x-4y)

[Hayleyanne]

I'm having a lot of trouble simplifying the following expression:

x^2 - y^2 - 4x + 4y
________over_______

x^2 - y^2 + 4x - 4y

PLEASE HELP!!!!!!!

 

[pka]

Re: Rational Expression Problem

\(\displaystyle \frac{{x^2 - y^2 - 4x + 4y}}{{x^2 - y^2 + 4x - 4y}} = \frac{{\left( {x - y} \right)\left( {x + y} \right) - 4\left( {x - y} \right)}} {{\left( {x - y} \right)\left( {x + y} \right) + 4\left( {x - y} \right)}} = \frac{{x + y - 4}} {{x + y + 4}}\)