若x-y-z=5,y-x=-2,则z=（ ） 若x+2y-3z=5,9z-6y=-2,则x=（ ）

若x+y+z=3y=2z,则x/x+y+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+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 若4x=7y+5z,2x+y=z,则x:y:z的值为 若x,y,z成等差数列,则(z-x)^2-4(x-y)(y-x)= (x+y-z)(x-y+z)= x/2=y/3=z/5 x+3y-z/x-3y+z 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) 若X/10=Y/8=Z/9则X+Y+Z/Y+Z=? 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. X/10=Y/8=Z/9,则X+Y+Z/2Y-3Z 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= 已知：4x-5y+2z=0 x+4y-3z=0则：(x*x+y*y+z*z)/(x*y+y*z+z*x)=____. 若z分之x+y+z=y分之x-y+z=x分之-x+y+z,求xyz分之(x+y)(y+z)(z+x)