x+y+2z=5 2x-y-z=4 3x+y-3z=10

题目

x+y+2z=5 2x-y-z=4 3x+y-3z=10

答案

x+y+2z=5 ①
2x-y-z=4 ②
3x+y-3z=10 ③
①+②;3x+z=9 ④
②+③ 5x-4z=14 ⑤
4×④+⑤; x=50/17 ⑥
⑥代入④；z=3/17 ⑦
⑥,⑦代入②;y=29/17