Question

I want answer.....................​

Answer 1

the answer will be (a)

by the formula of (a+b)² and (a-b)²

Answer 2

Answer:

162a² + 98b²

Step-by-step explanation:

in the first term,identity  

(a + b)² = a² + 2ab + b²   can be used

(9a + 7b)² = 81a² + 126ab + 49b²

in the second term,identity

(a - b)² = a² - 2ab + b²   can be used

(9a - 7b)² = 81a² - 126ab + 49b²

therefore,

(81a² + 126ab + 49b²) + (81a² - 126ab +49b²)

=81a² + 126ab + 49b² + 81a² - 126ab +49b²

≈ 162a² + 98b²