Q. 305.0( 1 Vote )

x2 - 4x – 21 = ?
A. (x - 3) (x - 7)

B. (x - 3) (x + 7)

C. (x + 3) (x - 7)

D. none of these

Answer :

We have,

x2 - 4x – 21


= x2 + 3x - 7x – 21


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


= (x + 3) (x - 7)


Hence, option C is correct

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