Réponses

2014-01-30T19:40:40+01:00
(2x+1)²-(2x+1)(x+3)

Développement:
(2x+1)²-(2x+1)(x+3)
=4x²+4x+1-(2x²+6x+x+3)
=4x²+4x+1-2x²-6x-x-3
=2x²-3x-2

Factorisation:
(2x+1)²-(2x+1)(x+3)
=(2x+1)(2x+1)-(2x+1)(x+3)
=(2x+1)(2x+1-x-3)
=(2x+1)(x-2)