已知x-4y-5z=0 -3x y 4z不等于0
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2x-3y-z=0(1)x+3y-14z=0(2)(1)+(2)3x-15z=0x=5z(2)*2-(1)6y-28z+3y+z=09y=27zy=3z代入(4x^2-5xy+z^2)/(xy+yz+
1、(1)+(2)×4得11x-33z=0∴x=3z把x=3z代入(2)得6z+y-8z=0∴y=2z把x=3z,y=2z代入x²+y²-z²÷xy+yz得原式=(9z&
上式等于(x-3y)^2+(y+2)^2++∣Z²-3Z+2∣=0由于上面三个都是非负数,所以这三个得解都是0解得x=3y=-6y=-2z=2或1得(X+Y)的Z次方的值=-8或64
x²-6xy+10y²+4y+|z²-3z+2|+4=0(x²-6xy+9y²)+(y²+4y+4)+|z²-3z+2|=0(x-
是X+Y/5=Y+X/6=Z+X/7吧由X+Y/5=Y+X/6解得,X=24Y/25把上式代入:Y+X/6=Z+X/7解得Z=179Y/175所以X:Y:Z=(24Y/25):Y:179Y/175=1
由2x-3y-z=0,x+3y-14z=0,且x,y,z不全为0解得x=5zy=3z将x=5zy=3z带入4x平方-5XY+Z的平方/xy+yz+zx得4*25z平方-5*5Z*3z+Z的平方/5z*
由3x-4y-z=0得z=3x-4y③由2x+y-8z=0得y=8z-2x④④代入③得x=3z⑤y=2z将x,y代入(x^2+y^2+z^2)/(xy+yz+2zx)=(9z^2+4z^2+z^2)/
4x-3y=3z.(1)x-3y=z.(2)(1)-(2)得3x=2zx=(2/3)z代入(2)得(2/3)z-3y=zy=-(1/9)z则xy+2yz/x²+y²+z²
2x+3y-5z=0,3x-2y+12z=0(z≠0),解得x=-2zy=3z所以2x*2-3xy/4x*2-12xy+9y*2=(8z²+18z²)/(16z²+72z
由4x-5y+2z=0,(1)x+4y-3z=0,(2)将2式乘以4减去1式,可以得出,21y=14z,即z=1.5y代回1式可得,4x-5y+3y=0,即4x=2y,x=0.5y分别代入(x
2x-3y-z=01X+3Y-14Z=021式+2式:3x-15z=0即x=5z31式-2*2式:-9y+27z=0即3z=y43式/4式:x/y=5/3即x=5y/3(4x^2-5xy+z^2)÷(
设k=x/3=y/4=z/6∴x=3k,y=4k,z=6k(xy+yz+xz)/(x²+y²+z²)=(12k²+24k²+18k²)/(9
3x-4y=z,2x+y=8z,解得:x=3z,y=2zxy+yz分之x二次方+y二次方-z二次方=(x^2+y^2-z^2)/(xy+yz)=(9z^2+4z^2-z^2)/(6z^2+2z^2)=
2x-3y-z=0(1)x+3y-14z=0(2)(1)+(2)3x-15z=0x=5z(2)*2-(1)6y-28z+3y+z=09y=27zy=3z代入(4x^2-5xy+z^2)/(xy+yz+
这个题目有值,说明这个题目和x、y、z的取值没有关系,因此,用特值法.假设y=0,x=1,z=2代入得(4x^2-5xy+z^2)/(xy+yz+xz)=8/2=4
解方程组:{2x-3y-z=0.(1){x+3y-14z=0.(2)(1)+(2)得:3x-15z=0即:x=5z,代入(1)式得y=3z所以:(4x²-5xy+z²)/(xy+y
6x-8y-2z=06x+3y-24z=011y-22z=0y=2z3x-4(2z)-z=0x=3z(x²+y²-z²)/(xy+yz)=[(3z)^2+(2z)^2-z
3x-y=-2zx+2y=-3z那么:x=-z,y=-z(3x^-xy+2y^)/(2x^+4xy+y^)=(3z^2-z^2+2z^2)/(2z^2+4z^2+z^2)=4z^2/7z^2=4/7