a) 3x+y=8
X=1-2y
3(1-2y)+y=8
X=1-2y
3-6y+y=8
X=1-2y
-5y=5
X=1-2y
Y=-1
X=1+2=3
b)3(x+2)+4y=-1
2x-4(y+2)=-6
3x+6+4y=-1
2x-4y-8=-6
3x+4y=-7
2x-4y=2
Le scadem:
X=-9
=>y=-5
c)x+y-9/x-2y=3/4
X+y/4-(3x-2y-6/6)=5/4
(x+y-9)*4=(x-2y)*4
3x+3y/12-(6y-4y-12/6)=15/12
4x+4y-36=4x-8y
3x+3y-6y+4y+12=15
4x-4x+8y+4y=36
3x+y=3
12y=36
3x+y=3
Y=3
3x+3=3
Y=3
X=0
