Cause I'm not sure of my answers
(#s 5,8,9 are factoring)
5. i'm stuck at completing the square, dunno what to add to 20x2y2 to make it a perfect square trinomial and then a difference of two squares.
8. totally lost on this one.
9. does this end up being [(xy -3x -y -3) (x2y2 -6x2y +9x2 +2xy2-18x +y2 +6y +9)]?
And if the question has more than two parts to it, it is best to post only that question and its parts in the thread and start a new thread for other questions.
I will do #8 and #9 before closing the thread:
8) The first three terms have a common factor and then can be factorised as a perfect square. Therefore you have .
Now let , factorise and then substitute back that .
9) You have . Now factorise each of these (they are differences of perfect cubes).
Thread closed (pm me if you need more help on 8) and 9). Be sure to say exactly where you're stuck).