Réponses

2013-11-24T10:04:15+01:00
A=6(3x²-4x+9) 
=18x²-24x+54

B=8x+x(-9x+4) 
=8x-9x²+4x
=-9x²+12x

C=5x-7(3x-2) 
=5x-21x+14
=-16x+14

D=x²-4x(4x-1) 
=x²-16x²+4x
=-15x²+4x

E=7x(5x-4)-2x(9-7x)
=35x²-28x-18x+14x²
=49x²-46x
2013-11-24T10:18:15+01:00
A = 6(3x²-4x+9)
   =18x²-24x+54
B = 8x+x(-9x+4)
   =8x-9x²+4x
   =-9x²+12x
C = 5x-7(3x-2)
   =5x-21x+14
   =-16x+14
D = x²-4x(4x-1)
   =x²-16x²+4x
   =-15x²+4x
E = 7x(5x-4)-2x(9-7x)
   =35x²-28x-18x+14x²
   =49x²-46x