Vérification :
A = (3x - 5)² - (4x + 8)(1 - x)
A = 9x² - 25 - 4x -4x² + 8 - 8x
A = 5x² -12x -17
B= (2x - 4)(2x + 4) + (2x - 4)(3 - 7x)
B= 4x² + 8x - 8x -16 + 6x -14x² -12 + 28x
B = -10x² +34x -28
C= (1 -4x)² - (7 + 5x)²
C= 1 - 16x² - 49 - 25x²
C= -41x² -48
D= 12x² -3(5x + 7) +20x
D = 12x² -15x - 21 + 20x
D= 12x² +5x -21