Réponses

2013-10-21T18:47:04+02:00
(x-4)(x+1)=x²+x-4x-4=x²-3x-4

3x²+6x+3=3(x²+2x+1)

-3(2x+2)(-3x-5)= -3(-6x²-10x-6x-10)=18x²+30x+18x+30=18x²+48x+30
2013-10-21T18:48:48+02:00
(x-4)(x+1)= x²+x-4x-4=x²-3x-4
3x²+6x+3= 3(x²+2x+1)
-3(2x+2)(-3x-5)=-3(-6x²-10x-6x-10)
                     = 18x²+30x+18x+30
                     =18x²+48x+30