2x+y=1,.(1)
4x-2y+z=3,.(2)
6x+y-3z=0.(3)
(1)-(3):
3z-4x=1...(4)
(3)*2+(2):
16x-5z=3.(5)
(4)*4+(5):
7z=7
z=1
x=1/2
y=0