Question

expand using identities (7x-9y) (7x + 9y)​

Answer 1

Answer:

Step-by-step explanation:

(7x - 9y) (7x - 9y)

= (7x - 9y)^2

Using this formula  [ (a-b)^2 = a^2 + b^2 - 2ab]

= (7x)^2 + (9y)^2 - 2(7x)(9y)

= 49x^2 + 81y^2 - 126xy

ANSWERED BY GAUTHMATH

Answer 2

Answer:

First method use formula:-

$(a + b)^3 = a^3 - 3a^2b + 3ab^ 2 - b^3$

Solution:-