3x-y+2z=13 (1)
2x+y-3z=11 (2)
x+y+z =12 (3)
(1)+(2)
5x-z=24 (4)
(1)+(3)
4x+3z=25 (5)
(4)×3+(5)
19x=97
x=97/19
z=5x-24=29/19
y=12-x-z=102/19