3) x2 + 4x - 21

A) (x - 3) (x - 7)

0) Not factorable

& (x-3) (x+7)

(x+3) (x-7)

(x - 3) (x + 7)

Step-by-step explanation:

x² + 4x - 21

Factor using the AC method.

1 * - 21 = - 21

Factors of - 21 that add up to 4: 7 and - 3

Divide by 1 and reduce: 7/1 and - 3/1

Factors are x + 7 and x - 3

x² + 4x - 21 = (x + 7) (x - 3)