已知4x-3y-3z=0,x-3y-z=0 求xy+2yz/x²+y²+z²

已知x+y+z=0求证x*x*x+y*y*y+z*z*z=3xyz 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 已知 x-3y+z=0 3x-3y-4z=0,则x:y:z=已知x-3y+z=0 3x-3y-4z=0则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 已知4x-3y+z=0,x+3y-3z=0,则x:y:z=( ) 已知{x-3y+2z=0 3x-3y-4z+0,则x:y:z=? 已知4x-3y-3z=0 x-3y-z=0 (1)求x:y:z 已知X-3Y+Z=0 3X-3Y-4Z=0.则X:Y:Z=? 已知x-2y+3z=0,x-3y+4z=0,则x:y:z= 已知2x-y-z=0,3x+4y-2z=0,则x：y：z=? 已知x+4y-3z=0,4x-5y+2z=0,则x：y：z 已知{x-5y+2z=0 3x-5y-4z=0,求x：y:z 已知方程组4x-5y+2z=0 x+2y=3z 则x:y:z 已知x/3=y/4=z/6≠0,求x+y-z/x-y+z的值 已知：4x-5y+2z=0 x+4y-3z=0则：(x*x+y*y+z*z)/(x*y+y*z+z*x)=____. (x+y):(y+z):(z+x)=3:4:5 3x+y-z=-4已知(x+y):(y+z):(z+x)=3:4:5 ；3x+y-z=-4求x y z 已知4x-3y-3z=0,① x-3y+z=0,②并且z不等于0,求x：z与y：z