3x=5y=6z怎么解

7x+2y-z=7,.(1)6x-y+z=7,.(2)4x+3y+z=9.(3)(1)+(2):13x+y=14y=14-13x.(4)(3)-(2):-2x+4y=2x=2y-1.(5)将(5)代入

{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

由1*4=8X+4Y+12Z=921X+4Y+5Z=362由1-27X+7Z=56X+Z=8由2*2=2X+8Y+10Z=7232X+Y+3Z=234由3-4=7Y+7Z=49Y+Z=7由1*5,2*

[x,y,z]=solve('x^2-5*y^2+7*z^2+12=0','3*x*y+x*z-11*x=0','2*y*z+40*x=0')

(1)+(2)-(3)=>z=7-8y把z=7-8y代入(1),(2)=>2x-20y=-123x-42y=-24=>x=-1,y=1/2,z=3

x-7y+3z=17方程15x-6y-z=24方程23x+7y-2z=1方程3方程1变为x=17+7y-32z代入方程2和方程3得5(17+7y+32z)-6y-z=24方程43(17+7y+32z)

x+y-z=6,①x-3y+2z=1,②3x+2y-z=-7③①-②得4y-3z=5④①*3-③得y-2z=25⑤④-⑤*4得5z=-95z=-19代入⑤得y+38=25y=-13代入①得x-13+1

x-z=2.5y=7/2

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：�

：①+②得,4x+3z=18④①+③得,2x-2z=2⑤④与⑤组成方程组：解这个方程组,得x=3z=2把代入便于计算的方程①,得y=1∴这个方程组的解为x=3y=2z=1注意：为把三元一次方程组转化为

x(x+y+z)=6(1)y(x+y+z)=12(2)z(x+y+z)=18(3)(1)/(2)x/y=1/2y=2x(1)/(3)x/z=1/3z=3xx(x+2x+3x)=66x^2=6x=1y=

哦买噶.晕倒.

y+z-3x=3,z+x-3y=5,x+y-3z=6,相加,-x-y-z=14,x+y+z=-14,4x=-17,x=-17/4,4y=-19,y=-19/4,4z=-20,z=-5

此题的意图在于x+y=?（用换元法）因此此题暗含需要在方程两式x+2y+3z=8；x+3y+5z=6中导出x+y有关的式子；因而涉及到要使用换元法,要在两式中导出x+y的新元；因此两式要乘公因式后相减

2x-3y+z=0(1)3x-2y-6z=0(2)(1)*2-(2)*34x-6y+2z-9x+6y+18z=0-5x+20z=05x=20zx=4z(1)*3-(2)*26x-9y+3z-6x+4y

x=-18y=-15z=195x-7y+z=34同乘以2后,与y-3x-2z=1相加,得到x=（69+13y)/7x+2y+3z=9同乘以3后,与y-3x-2z=1相加,得到z=4-y同时带入任何一个

x/2=y/3=z/5;x+y+z=20所以y=3x/2z=5x/2所以x+y+z=x+3x/2+5x/2=20所以x=4y=6z=10

应该是3X=4Y,5Y=6Z吧?X+Y：Y+Z=[(4Y/3)+Y]：(Y+5Y/6)=14;11

(1)x+2y+3z=11(1)x-y+4z=10(2)x+3y+2z=2(3)(1)-(2)得,3y-z=1,(4)(3)-(2)得,4y-2z=-8,即2y-z=-4,(5)(4)-(5),得y=