Originally Posted by **greenstupor**

I actually did that the first time. My first answers were:

1) $\displaystyle 3x^3 - 12y^3 - 8x^2y + 16xy^2$

2) $\displaystyle 4x^2 - 11x + 6$

However, she marked those two wrong. On a related note, there was another, similar problem which I got correct.

3) $\displaystyle (3x^2 - 5y^2)(2x - 4y)$

My **correct** answer was: $\displaystyle 6x^3 - 12x^2y - 10xy^2 + 20y^3$

After seeing that problem 3 was correct, but problem 1 was wrong, I tried to reorder my terms in problem 1 in the same way as I did in problem 3 ($\displaystyle x^3$ first, then $\displaystyle x^2y$, then $\displaystyle xy^2$, then $\displaystyle y^3$). However, she still marked it wrong. So, I'm completely stuck. Any more tips?