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a ) ( x - 1 ) ( 2 x + 5 ) + 4 x ² + 20 x + 25
= ( x - 1 ) ( 2 x + 5 ) + ( 2 x +5 )²
= ( 2 x + 5 ) ( x - 1 + 2 x + 5 )
= ( 2 x + 5 ) ( 3 x + 4 )
b) 9 x² - 81 - 2 x ( 3 x - 9 )
= ( 3 x - 9 ) ( 3 x + 9 ) - 2 x ( 3 x - 9 )
= ( 3 x - 9 ) ( 3 x + 9 - 2 x )
= ( 3 x - 9 ) ( x + 9 )
= 3 ( x - 3 ) ( x + 9 )
c ) 5 x - 20 - ( 2 x + 3) ( x - 4 )
5 ( x - 4 ) - ( 2 x + 3 ) ( x - 4 )
( x - 4 ) ( 5 - 2 x - 3 )
= ( x - 4 ) * -2 ( x - 1 )
= - 2 ( x - 4 ) ( x - 1 )
d ( 2 x + 1 ) - 6 x - 3
= ( 2 x + 1 ) - 3 ( 2 x + 1 )
= ( 2 x + 1 ) ( x - 3 )
a = ( 2 t - 1 ) ( t - 7 ) - t + 7
= ( 2 t - 1 ) ( t - 7) - ( t - 7 )
= ( t - 7 ) ( 2 t - 1 - 1 )
= ( t - 7 ) ( 2 t - 2 )
= 2 ( t - 7 ) ( t - 1 )
b = (6 x - 5 )² + 12 x - 10
= ( 6 x - 5 )² + 2 ( 6 x - 5 )
= ( 6 x - 5 ) ( 6 x - 5 + 2 )
= ( 6 x - 5 ) ( 6 x - 3 )
= 3 ( 6 x - 5 ) ( 2 x - 1 )
c) ( 3 z - 5 )³ - 2 z ( 3 z - 5 )²
= ( 3 z - 5 )² ( 3 z - 5 - 2 z)
= ( 3 z - 5 )² ( z - 5 )
( 4 x + 3 ) ( x - 1 ) + 2 x² - 2
= ( 4 x + 3 ) ( x - 1 ) + 2 ( x² - 1 )
= ( 4 x + 3 ) ( x - 1 ) + 2 ( x - 1 ) ( x + 1 )
= ( x - 1 ) ( 4 x + 3 + 2 x + 2 )
= ( x - 1 ) ( 6 x + 5 )