三元一次方程组:2X+Y-Z=5---(1) X-Y+2Z=-1---(2) X+2Y+Z=-2---(3)

问题描述:

三元一次方程组:2X+Y-Z=5---(1) X-Y+2Z=-1---(2) X+2Y+Z=-2---(3)

(1)+(3):3X+3Y=3即X+Y=1---(4)
2*(1)+(2): 5X+Y=9---(5)
(5)-(4): 4X=8 即X=2
从而解得Y=-1
Z=-2