Question

(7a² – 63b²) =? 

A. (7a – 9b) (9a + 7b) 

B. (7a – 9b) (7a + 9b) 

C. 9(a - 3b) (a + 3b) 

D. 7(a - 3b) (a + 3b)

Answer 1

(7a² – 63b²) = 7(a² – 9b²) (taking 7 as common from whole) 

= 7(a – 3b)(a + 3b) a² – b² = (a – b)(a + b)