Bonjour,

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

A = 10x + 5 - 3x - 6

A = 10x - 3x + 5 - 6

A = 7x - 1

B = 6 - (3x - 1) - (7x + 2)

B = 6 - 3x + 1 - 7x - 2

B = - 3x - 7x + 6 + 1 - 2

B = - 10x + 5

C = 4 (5x + 9) + (8x - 9)

C = 20x + 36 + 8x - 9

C = 20x + 8x + 36 - 9

C = 28x + 27

D = - (6x - 3) - (- 4x + 1) + 2 (8x - 7)

D = - 6x + 3 + 4x - 1 + 16x - 14

D = - 6x + 4x + 16x + 3 - 1 - 14

D = 14x - 12.