若x/2=y/3=z/4不等于0
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方程组两边除以z得4x/z-3y/z=3x/z-3y/z=-1解方程组得x/z=4/3y/z=7/9
x/2=y/3=z/4=kx=2k,y=3k,z=4k2x+3y-4z/x+y+z=(4k+9k-16k)/(2k+3k+4k)=-1/3再问:确定?
是3x+2y-x分之x-y-z吗?还是3x+2y-z分之x-y-z设x/2=y/3=z/4=K则x=2k,y=3k,z=4kx-y-z/3x+2y-z=2k-3k-4k/6k+6k-4k=-5k/8k
4x-y+3z=0(1)2x+y+6z=0(2)()+(2)6x+9z=06x=-9zz/x=-2/3(1)*2-(2)8x-2y-2x-y=06x-3y=06x=3yx/y=1/2z/x=-2/3x
30:3:5再问:稍微说一下理由谢谢!
解由5分之x=4分之y=3分之z令5分之x=4分之y=3分之z=k则x=5k,y=4k,z=3kk不等于0则3x-2y分之x+y+z=(3x-2y)分之(x+y+z)=(3*5k-2*4k)分之(5k
4x-5y+2z=0①x+4y-3z=0②由①+②得:5x-(y+z)=05x=y+z由②*4-①得:21y-14z=0y=2z/35x=2z/3+z=5z/3x=z/3x:y=(z/3):(2z/3
4x-3y-3z=x-3y+z=04x/z-3y/z-3=0.①x/z-3y/z+1=0.②①-②得:3x/z-4=0x/z=4/3代入②得:4/3+1-3y/z=0y/z=7/9x:y=(4/3)/
4x-3y-3z=0.1)x-3y+z=0.2)相减:3x=4zx/z=4/31)-2)*4:9y=7zy/z=7/9所以:x/z=4/3,y/z=7/9
4x-3y-3z=0(1)x-3y+z=0(2)(1)-(2):3x-4z=0x=4z/3代入(1):16z/3-3y-3z=0y=7z/9所以:x:z=4:3y:z=7:9
31x+19y-23应该是:31x+19y-23z,少了一个z就不好解答了4x-5y+2z=0①x+4y-3z=0②由①+②得:5x-(y+z)=0所以5x=y+z由②*4-①得:21y-14z=0所
由已知:x+2y-7z=0(1)4x-3y-6z=0(2)将(2)*4-(1)*5得:11x-22y+11z=0,即:x-2y+z=0(x+2y+z)/(x-2y-z)=(x+2y-7z+8z)/(x
(1)4x-3y-3z=0,(2)x-3y+z=0,(1)-(2)3x=4z;z=3/4x(1)+3(2)7x=12y;y=7/12x,x:y:z=12:7:9
由2x+3y-3z=0得:z-y=2x/3(2x+y-z)/(2x-y+z)=(2x-(z-y))/(2x+(z-y))将z-y=2x/3代入上式得:(2x+y-z)/(2x-y+z)=(2x-(2x
4x-3y+z=0(1)x+2y-8z=0(2)(1)-(2)×4得-11y+33z=0∴y=3z把y=3z代入(2)得x=2z把x=2z,y=3z代入x+y-z/x-y+2z得原式=(2z+3z-z
(x-3y+z)+(3x-3y-4z)=0,则4x=3y,x:y=3:4(x-3y+z)-(3x-3y-4z)=0,则2x=5z,x:z=5:2则x:y:z=20:15:8
(1/2)x=(1/3)y=(1/4)z=kx=2k,y=3k,z=4kx:y:z=2:3:4
(4x/z)-(5y/z)=-2……①(x/z)-(4y/z)=3……②方程②×4得,(4x/z)-(16y/z)=12……③①-③得,11y/z=-14,∴y/z=-14/11代入②得,(x/z)-
令a=x/2=y/3=z/4则x=2a,y=3a,z=4a所以原式=(2a+3a+4a)/(2a+3a-4a)=9a/a=9