Respuesta :

MathPhys

Answer:

(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)