若x/3=y/2=z/5则x^2-y^2-z^2/（xy+yz+zx）

若x+y+z=3y=2z,则x/x+y+z=? 若x/2=y/3=z/4,则3x-2y+5z/x+y+z= 若x/3=y/2=z/5,则2x-3y-z/x-y+z= 若2x=3y=5z,则3x-2y+z/x+y-z x/2=y/3=z/5 x+3y-z/x-3y+z 若x,y,z成等差数列,则(z-x)^2-4(x-y)(y-z)= 若x/2=y/3=z/4则3x-2y+5z/x+y+x= 若X:Y:Z=5:6:7那么(Y-X):(Y+Z)和(X+2Y+3Z):(3X+2Y+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 若x,y,z成等差数列,则(z-x)^2-4(x-y)(y-x)= 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? 已知：4x-5y+2z=0 x+4y-3z=0则：(x*x+y*y+z*z)/(x*y+y*z+z*x)=____. 三元一次方程组题目x+y-z=11 y+z-x=5 x-y+z=1x+y=4 y+z=3 x+z=5若已知x-3y+2z=0 2x+3y-8z=0, 且xyz≠0,则x:y:z= X/10=Y/8=Z/9,则X+Y+Z/2Y-3Z 若x/3=y/4=z/5则x+y/x-2y+3z=? 若x/4=y/4=z/5,则x+y/x-2y+3z=