Question

Subtract 2a² - 7ab + 9b² from a² - 3ab + 2b²​

Answer 1

- a² + 4ab - 7b²

Explanation :

Q. a² - 3ab+ 2ab² ; 2a² - 7ab + 9b²

= { a² - 3ab + 2ab² } -{ 2a² - 7ab + 9b²}

= a² - 3ab + 2ab² - 2a² +7ab - 9b²

= 1a² - 2a² - 3ab + 7ab + 2b² - 9b²

= - a² + 4ab -7b²

hope it helps you.....

Answer 2

This is your answer

Required experssion :

${a}^{2} - 3ab + 2 {b}^{2} ) - (2 {a }^{2} - 7ab + 9 {b}^{2} ) \\ = {a}^{2} - 3ab + 2{b}^{2} - 2 {a}^{2} + 7ab + 9 {b}^{2} \\ collecting \: postive \: and \: negative \: like \: term \: together \: we \: get \\ = {a}^{2} - 2 {a}^{2} - 3ab + 7ab + 2{b}^{2} - a {b}^{2} = - {a}^{2} + 4ab - 7 {b}^{2}$