Simplify: (3z − 9y)² + (9z + 3y)² − 81z²

Correct option is B

Given:

(3z − 9y)² + (9z + 3y)² − 81z² 

Formula Used: ​

​$$(a\pm b)^2 = a^2+b^2\pm2ab$$ 

Solution: ​

(3z − 9y)² + (9z + 3y)² − 81z²  

$$=9z^2 + 81y²-54xy + 81z^2 + 9y²+54xy - 81z² \\ \ \\ =9z^2 +90y^2$$​​