besoin d'aide svp exercice 6 Merci

A = 9a -9(x+1)
A = 9 ( a - x -1 )

B = 3b² + 3by
B = 3 x b x b + 3 x b x y
B= 3b(b+y)

C = (x-8)(x+3) - 5(x-8)
C = (x-8)(x+3-5)
C = (x-8)(x-2)

D = (2x + 5) (x +10) + (2x +5)
D = (2x + 5) (x +10) + (2x +5) ×1
D = (2x+5) (x+10 +1)
D = (2x +5) (x+11)

E = (3x-4)² - (3x-4)
E = (3x-4)² - (3x-4) × 1
E = (3x-4)(3x-4 -1)
E = (3x-4)(3x-5)