Question

c^(2)-c-72

Answer 1

(c+8)(c-9)

Answer 2

What are we doing with that?

Answer 3

factor

Answer 4

Then there it is, right above my first post. :)

Answer 5

to the asker: try to notice "why" the helpers used +8 and -9 instead of -8 and +9 (or some other factors of -72). You'll see that this factoring thing is actually pretty easy.