Thank you for all of your help. I'll ask my teacher tommorow.
Also, something does cancel out. If you factor x² + x - 30 you get (x + 6)(x - 5), and if you factor x² - 36 you get (x + 6)(x - 6). The (x + 6)' s cancel each other other out.
Yes, I'm positive about the 2x² + 9x -10. I guess my teacher didn't write the problem correctly.
I know how to factor the x² + x - 30 and the x² - 36, but not the other two.