Question

9c^2 -42c (a +b) + 49 (a+ b)^2)

Answer 1

Answer:

{3c - 7(a+b)}²

Step-by-step explanation:

= (3c)² +{7(a+b)}² -2×3c×7(a+b)

= by formula,

(a-b)²= a²+b²-2ab

: .{3c-7(a+b)}²