Réponses

2013-01-27T18:19:08+01:00

(2x+3)*2-(4x-5)*2 = (4x+6)-(8x-10) = 4x+6-8x+10=-4x+16

x=-1 doc A=-4*(-1)+16=4+16=20

 

 (2x+3)*2-(4x-5)*2=2(2x+3-4x+5)=2(-2x+8)=4(-x+4)

4(-x+4)=0 alors -x+4=0 alors x=4

 

voila, bon courage.

Meilleure réponse !
2013-01-27T18:19:28+01:00

A = (4x+6) -(8x-10) = 4x+6-8x+10

= -4x+16

 

si x = -1

 

A = 4+16 = 20

 

factorisation

 

4(-x+4)

 

-4x+16 =0

-4x = -16

x = -16/-4 = 4