Question

using suitable identity to get the product of (7a-9b)is​

Answer 1

(i) (7a − 9b) (7a − 9b) = (7a − 9b)2 = (7a)2 − 2(7a)(9b) + (9b)2 [(a − b)2 = a2 − 2ab + b2] = 49a2 − 126ab + 81b2