(x+y)/3=(y+z)/5=(z+x)/4 ,xyz不等于0,求x:y:z

x+y-z=3 y+z-x=5 z+x-y=7 求x,y,z x/2=y/3=z/5 x+3y-z/x-3y+z (x+y-z)(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.. (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(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? X+Y+Z=? x/y=(x+z)/(y+z)y/z=(x+y)/(x+z) {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 x+2y+3z=23 y-z=5 x+2z=10 设|x|-|y|+|z|=|x+y+z|,且|x+y|=4,|y+z|=5,|y|=3,求(x-y-z)^2的值 已知 x/(y+z)+y/(z+x)+z/(x+y)=1求 (x*x)/(y+z)+(y*y)/(x+z)+(z*z)/(x+y)=? 已知x/y+z=y/x+z=z/x+y,分式(x+2y+3z)/(2x+5y-2c)有意义时的值 x+y+z=35 2x-y=5 y/3=z/2 求x,y,z (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 已知x+y+z=0求证x*x*x+y*y*y+z*z*z=3xyz