I was wondering if someone could help me with a problem I am having with my nspire cas calculator. When I try to factor a perfect square trinomial like factor(4x^2 -36xy + 81y^2) it returns the following answer 4x^2+9(9y^2-4xy) instead of (2x-9y)^2, which is what the book that I am reading says it should be. I don't think that it is a calculator issue. I am more inclined to believe the problem is with me.
Thank you for posting a response. If I read your suggestion correctly, it was to place a multiplication symbol between the x and y of the second term. I gave it a go and it did the same thing. I did notice that the nspire always expands the equation out inserting multiplication symbols where it thinks they should go. I appreciate the help though.