Hey guys

Here's the solution to a question i had on a test

http://img832.imageshack.us/img832/5103/64344098.png

ok so i don't understand how they got from:

$\displaystyle -x^3/(3x-2)(2+3x)$

to

$\displaystyle {3x^2(4-3x^2)}/(2-3x)^2(2+3x)^2$

and i don't get how they find the "set numerator to 0" and "set denominator to 0" answers.

any help REALLY appreciated, thanks!