Réponses

2014-06-05T09:38:00+02:00
C)
6x+y=8
10x+7y=-8

y=8-6x
10x+7(8-6x)=-8

y=8-6x
10x+56-42x=-8

y=8-6x
-32x=-64

y=8-6x
x=2

y=8-6*2
x=2

y=-4
x=2

d)
7x+4y=-5
x+3y=9

7x+4y=-5
x=9-3y

7(9-3y)+4y=-5
x=9-3y

63-21y+4y=-5
x=9-3y

-17y=-68
x=9-3y

y=4
x=9-3*4

y=4
x=-3