如题x+2y-3z=0-y+2z=02x+2y-2z=0

若(z-x)2-4(x-y)(y-z)=0,求x+z-2y+2009如题 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 如题x+2y-3z=0-y+2z=02x+2y-2z=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^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+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 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 5x+3y-z=0,5x-3y+z=-4,10x+y+2z=-17/3如题 若x-y+z=-4,x^2-(y+z)^2=8,则x+y+z=如题 已知x>0 y>0 z>0 求证 (y/x+z/x)(x/Y+z/y)(x/z+y/z)>=8如题. 如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y, x/2=y/3=z/5 x+3y-z/x-3y+z x+2y=3x+2z=4y+z 求x:y:z x+y/2=z+x/3=y+z/4 x+y+z=27