Question

4. 25(2a - b)2 - 81b2
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Answer 1

Answer:

25(2a - b)2 - 81b2

= [ 5 ( 2a - b )]² - ( 9b)²

= ( 10a - 5b )² - ( 9b )²

= ( 10a - 5b + 9b )(10a -5b - 9b )

= ( 10a + 4b ) ( 10a - 14b )

= [ 2 ( 5a + 2b ) ] [ 2( 5a - 7b )]

= 4(5a - 7b )(5a+2b)