Question

x+2y+4z=17 2x+y+z=7 3x+y+2z=11

Answer 1

X+2Y+4Z=17.①

2X+Y+Z=7.②

3X+Y+2Z=11.③

③-②,得:

x+z=4.④

②+③-①,得:

4x-z=1...⑤

④+⑤,得:

5x=5

x=1

代入④,得:

1+z=4

z=3

再代入②,得:

2+y+3=7

y=2