5.{7x+2y-z=7 ① 6.{9x+4y+z=10 ①{6x-y+z=7 ② {-9x+2y+3z=-6 ②{4x+3y+z=9 ③ {3x-4y+2z=5 ③ x=1,y=1,z=2 x=1,y=0,z=1
来源:学生作业帮助网 编辑:作业帮 时间:2024/11/30 00:54:20
5.{7x+2y-z=7 ① 6.{9x+4y+z=10 ①{6x-y+z=7 ② {-9x+2y+3z=-6 ②{4x+3y+z=9 ③ {3x-4y+2z=5 ③ x=1,y=1,z=2 x=1,y=0,z=1
5.{7x+2y-z=7 ① 6.{9x+4y+z=10 ①
{6x-y+z=7 ② {-9x+2y+3z=-6 ②
{4x+3y+z=9 ③ {3x-4y+2z=5 ③
x=1,y=1,z=2 x=1,y=0,z=1
5.{7x+2y-z=7 ① 6.{9x+4y+z=10 ①{6x-y+z=7 ② {-9x+2y+3z=-6 ②{4x+3y+z=9 ③ {3x-4y+2z=5 ③ x=1,y=1,z=2 x=1,y=0,z=1
7x+2y-z=7 (1)
6x-y+z=7 (2)
4x+3y+z=9 (3)
(1)+(2)
13x+y=14 (4)
(1)+(3)
11x+5y=16 (5)
(4)×5-(5)
65x-11x=70-16
54x=54
x=1
y=14-13x=1
z=7x+2y-7=2
9x+4y+z=10 (1)
-9x+2y+3z=-6 (2)
3x-4y+2z=5 (3)
(1)+(2)
6y+4z=4
3y+2z=2 (4)
(2)+(3)×3
-10y+9z=9
10y-9z=-9 (5)
(1)×9-(2)×2
27y+20y=18-18
47y=0
y=0
z=(2-3y)/2=1
x=(5-2z+4y)/3=1
5. ①+ ②,13x+y=14 4
1+3,11x+15y=16 5
4*5, 64x+5y=70 6
6-5, 54x=54
x=1
把x=1代入4,y=1
把x=1,y=1代入1, z=2
6. 1+2, 6y+4z=4 4
③ *3,9...
全部展开
5. ①+ ②,13x+y=14 4
1+3,11x+15y=16 5
4*5, 64x+5y=70 6
6-5, 54x=54
x=1
把x=1代入4,y=1
把x=1,y=1代入1, z=2
6. 1+2, 6y+4z=4 4
③ *3,9x-12y+6z=15 5
5+2, -10y+9z=9 6
4*5+6*3, 47z=47
z=1
把z=1代入4,y=0
把y=0,z=1代入1, x=1
收起