J'arrive pas a l'exercice 66 besoin d'aide

A = 6 (3x² - 4x + 9)
A = 18x² - 24x + 54

B = 8x + x (- 9x + 4)
B = 8x + x - 9x + 4
B = 9x - 9x + 4
B = 4

C = 5x - 7 (3x - 2)
C = 5x - 21x + 14
C = - 16x + 14

D = x² - 4x (4x - 1)
D = x² - 16x² + 4x
D = - 15x² + 4x

E = 7x (5x - 4) - 2x (9 - 7x)
E = 35x² - 28x - 18x + 14x²
E = 35x² + 14x² - 28x - 18x
E = 49x² - 46x