x/10=y/5=z/7 x+y+2z=29 求x y z

x/10=y/5=z/7 x+y+2z=29 求x y z 已知4x-3y-6z=0,x+2y-7z=0,求5x+2y-z/2x-3y-10z (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+y+z=1;x+3y+7z=-1;z+5y+8z=-2 x+2y+3z=23 y-z=5 x+2z=10 x+y+z=14 7z=x+y+2 x+z=y (x+y-z)(x-y+z)= x+y+z=15 x+5y+10z=70 x,y,z,各是几? x+y+z=15 x+5y+10z=70 x,y,z,各是几? X+Y-Z=15 X+5Y+10Z=70 求：X、Y、Z x/2=y/3=z/5 x+3y-z/x-3y+z (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 fangchengzu:X+Z=Y 7Z=X+Y+Z X+Y+Z=14 用行列式的性质证明：y+z z+x x+y x y z x+y y+z z+x =2 z x y z+x x+y y+z y z x 这个怎么证? (x-2y+z)(x+y-2z)分之（y-x)(z-x) + (x+y-2z)(y+z-2x)分之(z-y)(x-y) + (y+z-2z)(x-2y+z)分之（x-z)(y-z)=?第三部分那个是 （y+z-2x)(x-2y+z)分之（x-z)(y-z) 若X:Y:Z=5:6:7那么(Y-X):(Y+Z)和(X+2Y+3Z):(3X+2Y+Z) 解方程组:x+y=5,y+z=7,x+2z=10