Bonjour,
A = (3x - 3) (2x + 8) + (3 - 5x) (2x + 8)
A = (2x + 8) (3x - 3 + 3 - 5x)
A = (2x + 8) (- 2x)
A = - 4x (x + 4)
B = (x + 1) (x + 2) - 5 (x + 2)
B = (x + 2) (x + 1 - 5)
B = (x + 2) (x - 4)
C = (2x + 1)² + (2x + 1) (7x - 3)
C = (2x + 1) (2x + 1 + 7x - 3)
C = (2x + 1) (9x - 2).
