(x - 9)(x-3)
multiply the first and last numbers of the equation to get 27
find two numbers that multiply to 27 and add to - 12 [the middle number]
- 9 and -3 multiply to 27 and add to - 12
because there is no coefficient on the x2, thats your answer. (x - 9)(x-3)
hope that makes some sense :)