Question 45614
(3+x+y)(-3+x-y)
Create the form (a-b)(a+b) as follows:
Rewrite as (x-(y+3))(x+(y+3))
=[x^2-(y+3)^2]
=[x^2-(y^2+6y+9)]
=x^2-y^2-6y-9

Cheers,
Stan H.