Réponses

2013-04-09T17:48:32+02:00

6x+8-5+10x=14x-21+12
16x+3-14x+9=0
2x+12=0
2x=-12
x=-6

2013-04-09T18:00:46+02:00

6x + 8 - 5  + 10x  =  14x - 21 + 12 

6x + 10x - 14x  =  - 21 + 12  - 8 + 5 

2x =  -12

 x = - 6

 voilà ;D