Question

解下列三元一次方程组x+y-z=0,x+2y-z=3

Answer 1

x+y-z=0 1

x+2y-z=3 2

2x-3y+2z=5 3

2-1式得y=3

将y=3代入2、3得

x-z=-3 4

x+z=7 5

4+5式得2x=4 解得x=2 y=5

综合得x=2 y=3 z=5