以知2x-3y+2z=0 x+y-z=0 那么xy+yz+xz除(x+y+z)的2次方的值是几?

证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 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 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. 已知x,y,z 大于0,x+y+z=2,求证 xz/y(y+z)+zy/x(x+y)+yx/z(z+x)大于等于2/3 2x+z=10 x+y-z=4 3x-y-z=0 若|x+3|+|y-2|+|2×z+1|=0求(x×z-y×z)(y-x+z)的值 以知2x-3y+2z=0 x+y-z=0 那么xy+yz+xz除(x+y+z)的2次方的值是几? 己知x+2y-3z=0,2x+3y+5z=0,求x+y+z/x-y+z的值. 如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y, 以知4x-3y-2z=0和x--3y+z=0的解一样且z不等于0,求x除以z和y除以z的值 以知方程组 4X—3Y—3Z=0 X—3Y—Z=0 求X：Z 和X：Y：Z 已知z、y、z同时满足x+3y-5z=0,2x-y-3z=0,求x:y:z 以知方程组{⑴4x-2y-6z=0⑵x-5y-7z=0.求7x+2y+6z/3x+5y+7z的值. {2x+y=10 {x-y+z=4 {3x-y-z=0 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z x>=y>=z>0,求证：x^2*y/z+y^2*z/x+z^2*x/y>=x^2+y^2+z^2