(1)y=2x-7 6x+3y+2z=2 3x-4z=4 (2) 4x+9y=12 3y-2z=1 7x+5z=19/4
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(1)y=2x-76x+3y+2z=23x-4z=4(2)4x+9y=123y-2z=17x+5z=19/4(1)y=2x-76x+3y+2z=23x-4z=4(2)4x+9y=123y-2z=17x
(1)y=2x-7 6x+3y+2z=2 3x-4z=4 (2) 4x+9y=12 3y-2z=1 7x+5z=19/4
(1)y=2x-7 6x+3y+2z=2 3x-4z=4 (2) 4x+9y=12 3y-2z=1 7x+5z=19/4
(1)y=2x-7 6x+3y+2z=2 3x-4z=4 (2) 4x+9y=12 3y-2z=1 7x+5z=19/4
1、把(1)代入(2)得
6x+6x-21+2z=2
12x+2z=23 (4)
(4)×2+(2)得
27x=50
∴x=50/27
把x=50/27代入(1)得
y=-89/27
把x=50/27代入(3)得
z=7/18
∴方程组的解是
x=50/27
y=-89/27
z=7/18
2、(1)-(2)×3得
4x+6z=9 (4)
由(3)得
28x+20z=19 (5)
(4)×7-(5)得
22z=44
∴z=2
把z=2代入(2)得
3y-4=1
∴y=5/3
把z=2代入(3)得
7x+10=19/4
x=-3/4
∴方程组的解是
x=-3/4
y=5/3
z=2
y=2x-7 ①
5x+3y+2z=2 ② 你的是6x 这里是5x,
3x-4z=4 ③
②×2:
10x+6y+4z=4 ④
③+④:
13x+6y=8 ⑤
把①代入⑤得:
13x+6(2x-7)=8
13x+12x-42=8
25x=50
∴x=2
代入①得:y=-3
代入③得:z=0.5
综上所述,解为:x=2,y=-3,z=0.5
x+y+z=6 x+2y+3z=14 y+1=z
(1)X+Y=15,Y+Z=-6,Z+X=7.(2)X+Y=-14,Y+Z=-7,Z+X=9.(3)X+Y=0,Y+Z=-1,Z+X=-1.
1.{x:y:z=3:4:5 2x+3y-5z=-142.{x-y-z=-1 3x+5y+7z=11 4x-y+2z=-13.{x+y=1 x+z=0 2x+y+2z=44.{x-y+z=-3 2x-y-z=-2 -3x+y+z=-15.{x-y+z=-3 3x+y-4z=6 2x+y-z=36.{x-2y+5z=16 2x+y-5z=7 2x-y+z=38
解三元一次方程组 ①2x-y+z=1 3x+y -2z=2 X+2y-z=3 ②x-4y+z=-3 2x+Y-Z=18 X-Y-Z=7 ③4x+4y+2z=7 6X-4y-z=6 2x-y+z=1
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..1.x+y+z=26,2.4y+3z=7,y-z=1,3x+2z=17,x+2y-z=18 9x-7y=173.x-7y+3z=17 4.2x+4y+3z=95x-6y-z=24 3x-2y+5z=113x+7y-2z=1 5x-6y+7z=131.x+y+z=26,y-z=1x+2y-z=18 2.4y+3z=7,3x+2z=11,9x-7y=17 3.x-7y+3z=17 5x-6y-z=24 3x+7y-2z=14.2x+4y+3z=93x-2y+5z=11 5x-6y+7z=13
(1)2X+4Y+3Z=93X-2Y+5Z=115X-6Y+7Z=13(2)X:Y=3:2Y:Z=5:4X+Y+Z=66(3)3X-Y+Z=32X+Y-3Z=11X+Y+Z=13以上3个题目为三元一次方程~
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解方程组 2x+3y-z=5 x-2y+2z=6 3x-y-3z=7{ 2x+3y-z=5 (1) { x-2y+2z=6 (2){ 3x-y-3z=7 (3)x=?y=?z=?
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