Question

- x^2 + 9x -18


i didn't explain....i need to factor...but i don;t get when there is a negative in front of the x


sorry
thanks

Answer 1

-x^2 factors to ... -x and x

find two factors of -18, that can sum to 9 (with a little sign adjustment)
... 6 and 3 will work ... with one of them negative

(-x + 6) and (x - 3) will FOIL to ... - x^2 + 9x -18

Answer 2

You can always do this for this type of question:

- x^2 + 9x -18
= -(x^2 - 9x + 18)
= -(x-3)(x-6) , which should have been easy to see

Now you could write that as:
(3-x)(x-6) or (x-3)(6-x)