Explicación paso a paso:
1)
2x+y=-2 x=-2-y/2
x-y=-4
[tex] \frac{ - 2 - y}{2} - y = - 4[/tex]
-2-y-2y=-8
-3y=-6
y=2
2x+2=-2
2x=-4
x=-2
2)
6x-3y=-6 2x-y=-3 =x=-3+y/2
x-y=-1
[tex] \frac{ - 3 + y}{2} - y = - 1[/tex]
-3+y-2y=-2
-3-y=-2
-y=1
y=-1
2x-(-1)=-3
2x+1=-3
2x=-4
x=-2
3)
2x+9y=39 x=39-9y/2
5x-y=-20
[tex]5 \times ( \frac{39 - 9y}{2} ) - y = - 20[/tex]
180-45y-2y=-180
-47y=-360
y=5
2x+45=39
2x=-6
x=-3
