急急急急急急！！！！ 解方程组 、、、要步骤 前面的括号就省略了 1、 2x+y-z=2 x+2y-z=5 x-y+z=-5

Question

2、x+y-z=6
x-3y+2z=1
3x+2y-z=4
3、x+y=3
y+z=5
x+z=6
4、y=2x-7
5x+3y+2z=2
3x-4z=4
5、4x+9y=12
3y-2z=1
7x+5z=4分之19
以上是三元一次方程组 、要步骤 如果好的话、悬赏还会加、
我已经作出来了 、
不用了、
关于下面除了第一个答案 、、
灰常谢谢、

Answer 1

1..............
2x+y-z=2 ---- ①
x+2y-z=5 -----②
x-y+z=-5 -----③
①+③等于3x=-3
②+③d等于2x+y=0
等于然后解新方程组 x=-1 y=2
带入①得，z=-2
方法就是这样子的 ..希望能帮的到你.........

Answer 2

x+y-z=6 ---- ①
x-3y+2z=1 -----②
3x+2y-z=4 -----③
①-②等于4y-3z=5
3乘以②-③等于-11y+7z=-1
然后解新方程组 z=-51/5 ； y=-352/55
带入①得，x方法就是这样子的 ..希望能帮的到你.........

Answer 3

1、(1) 2x+y-z=2 2、 (1) x+y-z=6 3、(1)x+y=3 4、(1) y=2x-7
(2) y+z=5 (2) 5x+3y+2z=2
(2) x+2y-z=5 (2) x-3y+2z=1 (3) x+z=6 (3) 3x-4z=4
(3) x-y+z=-5 (3) 3x+2y-z=4 (3)-(2) 由(3)两边X2+(2)得
有(1)-(2)得： 由（3）+（2）得 (4) x-y=1 (4) 13x+6y=8
（4）x-y=-3 (4) 7x+y=9 (1)-(4) (1)两边X6+(4)得
把（5）-（4）得 由（1）两边同乘2+（1） 2y=2 y=1 25x=50 x=2
z=-2, (5)3x-y=11 x+y=3 x=2 y=2x-7 y=-3
2x+y-z=2 (4+(5) x+z=6 z=4 3x-4z=4 z=0.5
2(y-3)+y-(-2)=2 10x=20 x=2
2y-6+y+2=2 由（5）得
3y-6+2=2 3x-y=11
3y=6 y=-5
y=2 由（1）得
x-y+z=-5 x+y-z=6
x-2-2=-5 z=-9
x=-1本回答被提问者和网友采纳

Answer 4

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