Question

2x-y-z=4
3x+4y-2z=11
3x-2y+4z=11

Answer 1

2x-y-z=4
3x+4y-2z=11
3x-2y+4z=11/*(-1)

3x+4y-2z=11
-3x+2y-4z=-11
---------------------- +
   6y-6z=0
y=z

2x-2y=4
3x+2y=11
-------------- +
5x=15
x=3
3-y=2
y=1
z=1
OTBET:  x=3, y=1, z=1.