方程组x-2y=z,3x+2y=1,2x-y=z+2分之1
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/31 14:56:07
x+2y+3z=80.1,x/2+y/3=z/4.2由2式得:6x+4y=3z代入1式得:7x+6y=80解有无数组,如:x=2,y=11,z=56/3x=4,y=26/3,z=176/9x=8,y=
①式+②式得x-y=5……④①式+③式得2x-5y=4……⑤2×④式-⑤式得y=2将y=2带入④式得x=7带入①式可得z=-2即x=7y=2z=-2
令k=x/2=y/3=z/4x=2k,y=3k,z=4k令a=√(x+2y+3z+2)则a²=x+2y+3z+2x+2y+3z=a²-2所以a²-2=a+4a²
解由2x+3y+z=11.①x+y+z=0.②3x-y+z=-2.③由(1)-(2)得x+2y=11.④由(2)-(3)得-2x+2y=2.⑤由(4)-(5)得3x=9即x=3把x=3代入④中解得y=
{3x+y-z=4①,2x-y+3z=12②,x+y+z=6③}①+②得5x+2z=16④,②+③得3x+4z=18⑤④×2—⑤得7x=14,x=2所以z=3、y=1所以方程组的解为x=2、y=1、z
设X为2a,Y为3a,Z为5a2*2a+3*3a-5a=16得a=2所以X=4Y=6Z=10
由2x=3yy=2z得x=1.5y=3z.(1)把(1)代入x+2y+z=16得z=2故:x=6,y=4
x:y=1:5=2:10,y:z=2:3=10:15,设x=2k,y=10k,z=15k,∵x+y+z=27,∴2k+10k+15k=27,k=1,∴x=2,y=10,z=15,故方程组的解是x=2y
由x+y/3=x+z/2得:y/3=z/2z=2y/3(1)由x+z/2=y+z/2得:x=y(2)把(1)和(2)代入x+y+z=28得:y+y+2y/3=288y/3=28y=21/2把y=21/
设(x+y)/2=(x+z)/3=(y+z)/4=k则x+y=2kx+z=3ky+z=4k代入x+y+z=272k+3k+4k=27k=3所以x+y=6(1)x+z=9(2)y+z=12(3)(1)+
4x-5y+2z=0(1)x+2y=3z(2)(2)×4-(1)得:13y=14zy=14/13z(1)×2+(2)×5得:13x=11zx=11/13z所以:x:y:z=11/13:14/13:1=
2,2,-2,8;1,-1,3,16;变换:1,1,-1,4;1,-1,3,16;变换:1,1,-1,4;0,-2,4,12;变换:1,1,-1,4;0,1,-2,-6;变换:1,0,1,10;0,1
x+y+z=41式x+y+2z=52式3x+y-z=63式2-1式z=13-2式2x-3z=14式z=1代入4式x=2再代入1式y=1∴x=2,y=1,z=1请点击下面的【选为满意回答】按钮,再问:�
设(x+y)/2=y+z/3=z+x/4=k∴x+y=2k,y+z=3k,x+z=4k∴2x+2y+2z=9k∵x+y+z=27∴k=6∴z=27-2×6=15x=4×6-15=9y=2×6-9=3
z=x+y(1)3x-2y-2z=-5(2)2x+y-z=3(3)由(1)得x+y-z=0(4)(3)-(4)得x=3把x=3代入(2)得9-2y-2z=-5y+z=7(5)把x=3代入(4)得y-z
x:y=1:2y=2xx:z=1:3z=3x2x+y-3z=152x+2x-9x=15-5x=15x=-3y=-3x2=-6z=-3x3=-9如果本题有什么不明白可以追问,
设2x=3y=6z=6K那么x=3ky=2kz=kx+2y+z=3k+4k+k=8k=16k=2所以x=6y=4z=2
先消去x,将x+2y+3z=14各乘3,及乘23x+6y+9z=42(*3)3x+y+2z=11相减得(1)5y+7z=312x+4y+6z=28(*2)2x+3y+z=11相减得(2)y+5z=17
x-2y+z=-1①x+y+z=2②x+2y+3z=-1③①+③2x+4z=-2x+2z=-1④①+②×23x+3z=-1+4x+z=1⑤由⑤得x=1-z代入④1-z+2z=-1z=-2∴x=1-(-
x+y-z=0(1)x+2y-z=3(2)2x-3y+2z=5(3)2-1式得y=3将y=3代入2、3得x-z=-3(4)x+z=7(5)4+5式得2x=4解得x=2y=5综合得x=2y=3z=5