Bonjour,
A = 6 (2x + 8)
= 12x+48
B = 7 (5x - 1)
= 35x-7
C = -4x (x - 9)
= -4x² +36
D = (3x + 4) (2x + 3)
= 6x² +9x +8x +12
= 6x² +17x +12
E = (7x + 5) (5x + (-3))
= (7x + 5) (5x -3)
= 35x² -21x +25x -15
= 35x² +4x -15
F = (2x + 9) (7x - 1)
= 14x² -2x +63x -9
= 14x² +61x -9