Difference of two squares : 9xy^2-16y?

Please be sure to include the instructions when you post a problem.

For example:  "Factor the difference of 2 squares 9xy^2 - 16y."

Unfortunately, your 9xy^2 is not a perfect square.  Please double check the original problem.  Did you mean      9(xy)^2 - 16?  Unfortunately, 16y is not a perfect square either.

If you had 9(xy)^2 - 16y^2, this would factor into (3xy + 4y)(3xy - 4y).