x2 + 4x – 21=? A. (x - 7) (x + 3) B. (x + 7) (x - 3) C. (x - 7) (

1.	x2 + 4x – 21=? A. (x - 7) (x + 3) B. (x + 7) (x - 3) C. (x - 7) (x - 3) D. (x + 7) (x + 3)
Answer» x² + 4x – 21 Factorizing the equation and taking x and – 3 as common, = x² + 7x – 3x – 21 = x(x + 7) – 3(x + 7) = (x – 3)(x + 7).

x2 + 4x – 21=? A. (x - 7) (x + 3) B. (x + 7) (x - 3) C. (x - 7) (x - 3) D. (x + 7) (x + 3)

Answer»

x² + 4x – 21

Factorizing the equation and taking x and – 3 as common,

= x² + 7x – 3x – 21

= x(x + 7) – 3(x + 7)

= (x – 3)(x + 7).