Bonjour,
Développer:
A = (x + 3)(x + 2)= x²+3x+2x+6= x²+5x+6
B = (x + 3)(2x +4)= 2x²+6x+4x+12= 2x²+10x+12
C = (x - 7)(x + 9)= x²-7x+9x-63= x²+2x-63
D= (x – 3)(4 – x)= 4x-12-x²+3x= -x²+7x-12
E = (3x + 4)(5x - 7)= 15x²+20x-21x-28= 15x²-x-28
F=(-2x + 8)(4 - x)= -8x+32+2x²-8x= 2x²-16x+32
