bonsoir

A = 6 x - 9 + ( 2 x - 3 ) ( 3 x + 1 )

=  3 ( 2 x - 3 ) + ( 2 x - 3 ) ( 3 x + 1 )

= ( 2 x - 3 ) ( 3 + 3 x + 1 )

= ( 2 x - 3 ) ( 3 x + 4 )

B = ( 4 x + 5 )² +  2 ( 4 x + 5 )

= ( 4 x + 5 ) ( 4 x + 2 + 2 )

 = ( 4 x + 5 ) (  4 x + 4 )

 = 4 ( 4 x + 5 ) ( x + 1 )

C =  (3 x - 1 ) ( 5 x + 4 ) -  2 ( 3 x -  1 )

= ( 3 x - 1 ) ( 5 x + 4 - 2 )

= ( 3 x - 1 ) ( 5 x + 2 )