解方程组{x:y:z=2:3:4
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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
x−43=y+14=z+25①x−2y+3z=30②,由①可设x−43=y+14=z+25=k,x=3k+4,y=4k-1,z=5k-2,代入方程②得,3k+4-2(4k-1)+3(5k-2)=30,
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)+
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:�
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
x-2y=-9-----------------①y-z=3--------------------②2z+x=47----------------③①-③-2y-2z=-9-47=-56-----④
x+y=3①y+z=5②z+x=4③,①-②得:(x+y)-(y+z)=3-5,即x-z=-2④,③+④得:(x-z)+(z+x)=-2+4,即2x=2,解得:x=1,把x=1代入④得:1-z=-2,
设x/2=y/3=z/4=k则有x=2ky=3kz=4k2x+y+z=224k+3k+4k=22k=2x=4y=6z=8
设x=2ky=3kz=4k则4k+3k+4k=22k=2会了么?
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