Réponses

2014-02-12T18:10:24+01:00
(5x-8)²+(5x-8)=(5x-8)((5x-8)+1)=(5x-8)(5x-7)

(2x+5)²-81=(2x+5)²-9²=(2x+5+9)(2x+5-9)=(2x+14)(2x-4)