Question

factorise
$45(a + b {)}^{2} (a - b {)}^{2} - 18(a + b)(a - b)$

Answer 1

Solution :

45( a + b )²( a - b )² - 18( a + b )( a - b )

= 9( a + b )( a - b ) [5 (a+b)(a-b)-2 ]

= 9( a + b )( a - b )[ 5(a²-b²) - 2 ]

= 9( a + b )( a - b )( 5a² -5b² - 2 )

••••