We have,x2 - 4x – 21= x2 + 3x - 7x – 21= x (x + 3) - 7 (x + 3)= (x + 3) (x - 7)Hence, option C is correct

Q30 of 274 Page 82

x² - 4x – 21 = ?

We have,

x² - 4x – 21

= x² + 3x - 7x – 21

= x (x + 3) - 7 (x + 3)

= (x + 3) (x - 7)

Hence, option C is correct

4x² + 4x – 3 = ?

6x² + 17x + 5

If (x + 5) is a factor of p (x) = x³ – 20x + 5k, then k =?

3x³ + 2x² + 3x + 2 = ?

x2 - 4x – 21 = ?