Réponses

2014-03-22T21:03:40+01:00
Bonsoir

A = (5x+2)(5x+2 -3x +1)
A = (5x +2)( 2x +1)

A = 0
si
5x +2 = 0 ⇒5x = -2 et x = -2/5
ou
2x +1 = 0 ⇒2x = -1 et x = - 1/2
Meilleure réponse !
2014-03-22T21:06:14+01:00
A= (5x+2)²-(3x-1)(5x+2) 
(5x+2)²-(3x-1)(5x+2) =0
(5x+2)((5x+2)-(3x-1))=0
(5x+2)(2x+1)=0
5x+2=0 ou 2x+1=0
5x=-2 ou 2x=-1
x=-2/5 ou x=-1/2
x=-2.5 ou x=-0.5