Réponses

2014-02-08T18:37:57+01:00
(3x-1)²-2(3x-1)(7x+3)= (3x-1)[(3x-1)-2(7x+3)
                                 =(3x-1)(3x-1-14x-6)
                                 = (3x-1)(-11x-7)
(3x+2)(7x+4)-3x-2 = (3x+2)(7x+4) -(3x+2)
                              = (3x+2) (7x+4-1)
                              = (3x-2)( 7x+3)
                              

 
Pourquoi tu transposes le -2 à (7x+3) et non plus à (3x-1) ?