Question

2x一y=z，x一y=一z怎么解得x=2z，y=3z的要详细过程谢谢

Answer 1

你好，解题过程如下
因为2Ⅹ一y=z，所以z=2x-y将此式代入x－y=-z
x-y=－(2x-y)
x-y=-2x+y
x=2/3y
将x=2/3y代入2x-y=z式，得
2*2/3y-y=z
1/3y=z
y=3z
将y=3z代入x-y=-z式，得
x-3z=－z
x=3z-z
x=2z

Answer 2

设2x一y=z为等式1，x一y=一z为等式2
等式1-等式2，就可以得到x=2z

2x一y=z
- x一y=一z
——————
x=2z

等式1-2*等式2，就可以得到y=3z

2x一y=z
- 2x一2y=一2z
——————
y=3z

Answer 3

2x-y=z (1)
x-y=-z (2)
(1)-(2)得
x＝z-(-z)=2z
把x=2z代入（1）得
2×2z-y=z
y=4z-z
y=3z

Answer 4

2x-y=z (1)
x-y=-z (2)
(1)-(2)
2x-x=z+z
x=2z
from (1)
2x-y=z
4z-y=z
y=3z