



 
Hi Jacky, To a large extent factoring involves recognizing patterns. In the expression
The pattern I recognize is x^{2}  y^{2} which can be factored as a difference of squares
Can you now see how to complete the problem? If you need further assistance write back, Jacky wrote back
Jacky, I don't think there is a simpler form unless it's the original x^{2}  y^{2} + 4x + 4y. The simplest or most useful form of a mathematical expression depends on how you are going to use the expression. Writing an expression in factored form as you did here, (x + y)(x  y + 4), is quite often the most usual way to express it. Penny  


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