2x-y+z=0 3x+8y-z=0 且xyz不等于0,求(2x²-xy+z²)/(2x²+y²-z²)的值

已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. 已知3x-4y-z=0,2x+y-8z=0,且z≠0,则x：y：z=（ ） 已知 (x+y-z)/z=(x-y+z)/y=(y+z-x)/x,且xyz≠0,求代数式 ((x+y)(y+z)(x+z))/xyz 若xyz≠0且4(x/z)-5(y/z)=-2,(x/z)+4(y/z)=3,求x:y:z 若x、y、z均不等于0,且2x+y-z=0 x+8y+2z=0,则x:y:z=? 已知方程组{2x-3y+z=0 且x*y*z不等于0 求 x：y：z {3x-2y-6z=0 已知2x-y-3z=0 x-2y+z=0,且x、y、z都不等于0,求x：y：z 已知方程组4x-y+3z=0 2x+y+6z=0且xyz不等于0,则x/y+y/z+z/x是多少 若(4x-3y-3z)^2+|x-3y-z|=0 且xyz不等于0 则4x+y-z/x+y+z 的值 已知x/2=y/3=z/4,且x+y+z不等于0,求2x+3y-4z/x+y+z的值 已知x/2=y/3=z/4,且x+y+z不等于0,求2x+3y-4z/x+y+z的值 X,y,z>0且x+y+z=1,求证：（1/x-x)(1/y-y)(1/z-z)≥(8/3)^3 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 三元一次方程组题目x+y-z=11 y+z-x=5 x-y+z=1x+y=4 y+z=3 x+z=5若已知x-3y+2z=0 2x+3y-8z=0, 且xyz≠0,则x:y:z= 已知xyz不等于0,且{x+3y+5z=0 x2+3y+z=0,则x.x+y.y-2z.2z/3x.3x+2y.2y+z.z=? 已知：(x+y-z)/z=(x-y+z)/y+(y+z-x)/x,且xyz≠0,求代数式[(x+y)(y+z)(x+z)]/xyz的值已知：(x+y-z)/z=(x-y+z)/y=(y+z-x)/x,且xyz≠0,求代数式[(x+y)(y+z)(x+z)]/xyz的值 题目中写错个等号，汗... 已知：x^2/(z+y)+y^2/(x+z)+z^2/(x+y)=0,求x/(z+y)+y/(x+z)+z/(x+y)的值. x^2/(z+y)+y^2/(x+z)+z^2/(x+y)=0,求x/(z+y)+y/(x+z)+z/(x+y)的值