Réponses

2013-03-05T22:46:18+01:00

Bonsoir

1)

E = (12+3x)(2x-7) -(2x-7)²

E = 24x-84+6x²-21x-(4x²+49-28x)

E = 2x²+31x-133

2)

E = (2x-7)( 12+3x-2x+7)

E = (2x-7)(x+19)

4)

(2x-7)(x+1) = 0 si un des facteurs = 0

2x-7 = 0   si x = 7/2

x+1 = 0 si  x = -1