Question

Which of the binomials below is a factor of this trinomial? x2 - 7x - 18

Answer 1

(x+2)(x-9) 

x^2 - 7 x - 18
The factors of -18 that sum to -7 are 2 and -9. So, x^2 - 7 x - 18 = (x + 2) (x - 9):
Answer:  (x + 2) (x - 9)