posted by Mae .
hi, could someone please explain how to factor this?
Start with the parentheses.
(    )(    )
The only way we can obtain 3x^2 is with 3x and x so put those in first. The only way we can get the last term is y and y so put those in next. The only way we can get a - term for the y^2 to to have one sign with the parentheses + and the other -. Just place them so the middle term is -2xy.
(3x+y)(x-y). User the FOIL method to check it. 3x^2 -3xy + xy -y^2 =
Check my work.
thanks so much! i finally understand it