若x+3y+5z=10,5x+z+3y=8,x+y+z=?若x+3y+5z=10,5x+z+3y=8,则x+y+z= 注明思路

若3x+7y+z=5,4x+10y+z=3,则x+y+z=? (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? 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+2y+3z=23 y-z=5 x+2z=10 (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. 若X:Y:Z=5:6:7那么(Y-X):(Y+Z)和(X+2Y+3Z):(3X+2Y+Z) (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 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= {2x+3y-4z=-5 x+y+z=6 x-y+3z=10 3x+2y+z=14 ,x+y+z=10,z+2x+3y=1 5 x+y+2z=5 2x-y-z=4 3x+y-3z=10 2x+y-z=3 5x+3y-z=10 求x+y+z= 若2x=3y=5z,则3x-2y+z/x+y-z 若x/3=y/4=z/5,求x+y+z/3x-2y+z的值. 若x：y：z=1:3:5,求分式x+3y-z/x-3y+z的值