若2x-y=3,2y-z=4,2z-x=5,则x+y+z=?

若x+y+z=3y=2z,则x/x+y+z=? x+2y=3x+2z=4y+z 求x:y:z x+y/2=z+x/3=y+z/4 x+y+z=27 若x,y,z成等差数列,则(z-x)^2-4(x-y)(y-z)= 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 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 x=y/z=z/3,x+y+z ＝12,求2x+3y+4z是多少, 若x/2=y/3=z/4,则3x-2y+5z/x+y+z= 若x/3=y/4=z/5,求x+y+z/3x-2y+z的值. 若x:y:z=2:3:4,求x+y+z/x-2y+3z的值 若x/2=y/3=z/4不等于0,求x+y+z/x+y-z的值 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 若xyz≠0且4(x/z)-5(y/z)=-2,(x/z)+4(y/z)=3,求x:y:z (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? 若4x-3y-6z=0,x+2y-7z=0,则x+y+z/3x-y+z=? x/2=y/3=z/5 x+3y-z/x-3y+z