Réponses

2013-10-16T21:18:16+02:00
(x+1)²-(x-1)²=x²+2x+1-(x²-2x+1)=x²+2x+1-x²+2x-1=4x
2013-10-16T21:21:17+02:00
F = ( x + 1 ) ²  - ( x - 1 ) ²  est du type a²-b²=(a+b)(a-b) donc
F= (x+1+x-1)(x+1-x+1)=(2x)(2)=4x