Question

the sum of 7x² + 8xy + 9z² and -7z² + 5x²- 11xy is:

1. 12x²-3xy+2z²
2. 10x²+4xy+2z²
3. 2x²- 19xy+ 16z²
4. 12x²-13xy-4z²​

Answer 1

answer is 1)

Hope you get your answer...

please mark me as brainliest..

thank you..

Answer 2

Answer:

Step-by-step explanation:

Sum of 7x² + 8xy + 9z² and - 7z² + 5x² - 11xy

= 7x² + 8xy + 9z² + ( - 7z² + 5z² - 11xy )

= 7x² + 8xy + 9z² - 7z² + 5z² - 11xy ( ∵ + × - = - )

= ( 7x² - 7x² ) + ( 8xy - 11xy ) + ( 9z² + 5z² ) ( ∵like terms adding )

= ( 0 ) + ( - 3xy ) + ( 14z² )

= - 3xy + 14z² is the answer.