Question

Factor completely. 9x^2-6xy+y^2-81

Answer 1

9x² - 6xy + y² - 81
= ( 9x² - 6xy + y² ) - 81
= ( 9x² - 6xy + y² ) - ( 9 )²

First bracket = a² - 2ab + b² = ( a - b )²
= [ ( 3x )² - 2( 3x )( y ) + ( y )² ] - ( 9 )²
= ( 3x - y )² - ( 9 )²

Difference of 2 squares = a² - b² = ( a + b )( a - b )
= ( 3x - 9y + 9 )( 3x - 9y - 9 )

Hope this helps

Answer 2

whts the answer

Answer 3

(3x - y - 9)(3x - y + 9)