Question 469233
1) x+y+z=4
2) x+y-z=6
3) x-3y+z=-1
...
1) x+y+z=4
2) x+y-z=6
add to eliminate z
4) 2x+2y=10
..
2) x+y-z=6
3) x-3y+z=-1
add to eliminate z
5) 2x-2y=5
..
4) 2x+2y=10
5) 2x-2y=5
add to eliminate y
4x=15
x=15/4
2y=2x-5=15/2-5=15/2-10/2=5/2
y=5/4
z=4-x-y=4-15/4-5/4=16/4-15/4-5/4=-4/4=-1
Check:
1) x+y+z=15/4+5/4-1=20/4-4/4=16/4=4
2) x+y-z=15/4+5/4+1=20/4+4/4=24/4=6
3) x-3y+z=15/4-3(5/4)-1=15/4-15/4-1=-1