bonjour

C = 8 ( a - b )

D =  manque des lettres je suppose

E = 2 ( 1 + x )

F = 7 ( a + 1 )

G = 4 x ( x - 1 )

H = 6 y ( 1 - y )

I = x ( 3 x + 5 )

J =   b ( 2 a + b )