(1)3x+4y=15 2y-z=2 x+2z=9 (2) x+y+z=8 2x+3y-z=6 3x-y+z=8 (3)

3x+4y=15
2y-z=2
x+2z=9
y=(2+z)/2
x=9-2z
3(9-2z)+4+2z=15
z=4 y=3 x=1
x+y+z=8 (1)
2x+3y-z=6 (2)
3x-y+z=8 (3)
(1)+(2) 3x+4y=14
(1)-(3) -2x+2y=0
x=y
x=2 y=2 z=4
2x+y+z=16 (1)
3x+2y+4z=44 (2)
x+3y+5z=52
6x+3y+3z=48
x-2z=-12
-5x+2z=4
-4x=-8
x=2 z=7 y=5