Question

﹛x+y+z＝12﹛x+2y-z＝6﹛3x-y+z＝10

Answer 1

解x+y+z＝12.1

x+2y-z＝6.2

3x-y+z＝10.3

1+2得2x+3y=18.4

2+3得4x+y=16.5

5式乘以3-4得10x=30

即x=3,y=4代入1得z=5

即x=3,y=4,z=5