Question

解方程组{2x-3y=1 2x-z=5 x+3y+z= 4

过程要详细，什么式子1，式子2，消去，代入之类的都写明白，

Answer 1

2x-3y =1 (1)
2x -z =5 (2)
x+3y+z = 4 (3)
(2)+(3)得
3x+3y=9 (4)
(1)+(4)得
5x=10
∴x=2
把x=2代入(1)得
4-3y=1
∴y=1
把x=2代入(2)得
4-z=5
∴z=-1
∴x=2
y=1
z=-1

Answer 2

2x-3y=1 (1)
2x-z=5 (2)
x+3y+z= 4 (3)

(2)+(3)
3x+3y=9 (4)
所以x+y=3 (5)
(1)+(4)
5x=10
所以
x=2
y=3-x=1
z=2x-5=-1

Answer 3

2x-3y=1 y=2x/3-1/3
2x-z=5 z=2x-5
x+3y+z= 4 x+(2x-1)+2x-5=4
x=2 y=1 z=-1