Réponses

  • Utilisateur Brainly
2014-05-03T11:35:43+02:00
6x - 3y = 36
9x + 7y = -31

par combinaison

-9(6x-3y) = 36
+6(9x+7y) = -31

-54x+27y = - 324
+54x+42y = -186
69y = -510
y = -170/23

9x+7y = -31
9x+(-1190/23) = -31
9x = 1190/23 -31
9x = (1190-713)/23
9x = 477/23
x = 53/23

verif :

6x - 3y = 36

(6*53/23) - (3*-170/23) = 36

318/23 +510/23 = 36
36 = 36