Question

Show that (3a- 7b)^2 + 84ab = (3a + 7b)^2

Answer 1

Answer:

Firstly we solve LHS

(3a-7b)^2+84b

(3a)^2-2×3a×7b+(7b)^2+84b

9a^2-42ab+49b^2+84ab

9a^2+42ab+49b^2

Now we solve RHS

(3a)^2+2×3a×7b+(7b)^2

9a^2+42ab+49b^2

Hence proved LHS = RHS

Answer 2

Step-by-step explanation:

(3a-7b)²+84ab

= (3a)² + (7b)² - 2x3ax7b + 84 ab

= 9a+49b- 42ab + 84ab

= 9a+49b +42ab

= (3a)² + (7b)² + 2x3ax7b

= (3 a+7b)² [∵a+b+2ab= (a+b)]

Hence, proved that

(3 a-7b)² +84ab= (3a+7b)²