1)
2x+y=1 y=1-2x
5x+2y=0
5x+2(1-2x)=0
5x+2-4x=0
x=-2
y=1-2(-2)
y=5
x=-2; y=5
2)
x-2y=7 x=7+2y
x+2y=-1
7+2y+2y+1=0
4y=-8
y=-2
x=7+2(-2)
x=3
x=3; y=-2.
1)
2x+y=1 y=1-2x
5x+2y=0
5x+2(1-2x)=0
5x+2-4x=0
x=-2
y=1-2(-2)
y=5
x=-2; y=5
2)
x-2y=7 x=7+2y
x+2y=-1
7+2y+2y+1=0
4y=-8
y=-2
x=7+2(-2)
x=3
x=3; y=-2.