1. ## Simplifing rational espressions

2z^2 - 11z + 15 / z - 9

This is what I did.
I times 2 and 15 and got 30. To get -11, I got -6 -5 which gives me 30 and -11. THe bottom I did (z-3)(z+3)
This is my final answer. (2z-6)(2z-5) / (z-3)(z+3)
Why was it marked wrong?
Thanks

2. For one thing, $z-9\neq (z-3)(z+3)$

But, assuming that is a typo, after factoring the num. and den. you get:

$\frac{(z-3)(2z-5)}{(z+3)(z-3)}$

Now cancel the z-3 and you're left with $\frac{2z-5}{z+3}$