Réponses

2014-05-22T23:59:49+02:00
X-3y=-5 donc x=3y-5
7x+8y=19
7x+8y=7(3y-5)+8y=21y-35+8y=19
29y=54
y=54/29
x=3*54/29-5=(162-145)/29=17/29