Réponses

2014-02-12T00:40:46+01:00
(5-2x)(5+2x)-2(3x+1)(5-2x)-(5-2x)²= (5-2x) [ ( 5+2x - 2(3x-1) - (5-2x)]
                                                      =( 5-2x) ( 5+2x -6x+2 -5 +2x)
                                                      = (5-2x) ( 2 -2x)
                                                      = (5 -2x) 2(1-1x)