3) Factor x2 - 8x - 9.

Check

(x-9) (x+1)

Step-by-step explanation:

factor using the box method or quadratic formula.

(x - 9) (x + 1)

Step-by-step explanation:

Given

x² - 8x - 9

Consider the factors of the constant term ( - 9) which sum to give the coefficient of the x - term ( - 8)

The factors are - 9 and + 1, since

- 9 * 1 = - 9 and - 9 + 1 = - 8, thus

x² - 8x - 9 = (x - 9) (x + 1)