X/4=Y/5=Z/7则x+y+z/z=?

X/4=Y/5=Z/7则x+y+z/z=? 若3x+7y+z=5,4x+10y+z=3,则x+y+z=? 若4x=7y+5z,2x+y=z,则x:y:z的值为 (x+y-z)(x-y+z)= 已知关于x y z的方程组2x-3y+5z=7 x+2y-3z=8,则4x+y-z= x+y-z=3 y+z-x=5 z+x-y=7 求x,y,z fangchengzu:X+Z=Y 7Z=X+Y+Z X+Y+Z=14 x-4y+z=-302x+y-z=18x--y-z=7 若x,y,z成等差数列,则(z-x)^2-4(x-y)(y-z)= 已知x:4=y:5=z:6.则x:y:z= (x+y):(y+z)= X+Y+Z=? x/y=(x+z)/(y+z)y/z=(x+y)/(x+z) 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 x/(y+z)+y/(z+x)+z/(x+y)=1求 (x*x)/(y+z)+(y*y)/(x+z)+(z*z)/(x+y)=? 5x+4y+z=-7 4x+y-4z=-13 x+y+z=0 2x+5y+4z=6,3x+y-7z=-4,x+y-z=? 已知X+4Y+Z=24,2X+7Y+2Z=41,则x:y:z=