Réponse :
Bonjour,
A = (7-3x)(9x-3)
A = 7*9x+7*(-3)-3x*9x-3x*(-3)
A = 63x-21-27x²+9x
A = -27x²+72x-21
B = (-2-3y)(4-8y)
B = -2*4-2*(-8y)-3y*4-3y*(-8y)
B = -8+16y-12y+24y²
B = 24y²+4y-8
C = (4a+6)(-3-5a)
C = 4a*(-3)+4a*(-5a)+6*(-3)+6*(-5a)
C = -12a-20a²-18-30a
C = -20a²-42a-18
D = (5z-7)(8z+2)
D = 5z*8z+5z*2-7*8z-7*2
D = 40z²+10z-56z-14
D = 40z²-46z-14
