3X+2Y+Z=13 (1)
X+Y+2Z=7 (2)
2X+3Y-Z=13 (3)
(1)*2得6X+4Y+2Z=26 (4)
(3)*2得4X+6Y-2Z=26 (5)
(4)-2得5X+3Y=19 (6)
(5)+(2)得10X+10Y=52 (7)
有(6)(7)可得X=19/10
Y=7/2
代入(2)的
Z=4/5
所以X=19/10
Y=7/2
Z=4/5