bonjour
C = ( x - 5) ( 2 x - 1 + 3 x + 7 )
= ( x - 5 ) ( 5 x + 6 )
D = ( 2 x + 5 ) ( x - 3 - 3 x + 1 )
= ( 2 x + 5 ) ( - 2 x - 2 )
= 2 ( 2 x + 5 ) ( - x - 1 )
E = ( 3 x + 7 ) ( 2 x - 9 - 5 x + 7 )
= ( 3 x + 7 ) ( - 3 x - 2 )
F = ( - 3 x + 4) ( 3 x - 8 - 7 x - 2 )
= ( - 3 x + 4 ) ( - 4 x - 10 )
G = ( 8 y + 3 ) ( 5 y + 7 - 6 y + 3 )
= ( 8 y + 3 ) ( - y + 10 )