已知2x+3y+z=6和x-y+3z=-1,求x+2y-z=?

已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 已知4X-3Y-3Z=0和X-3Y-Z=0 求3x-2z+y：-x+y+z的值 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. 已知x,y,z 大于0,x+y+z=2,求证 xz/y(y+z)+zy/x(x+y)+yx/z(z+x)大于等于2/3 已知2x+5y+4z=6 3x+y-7z=-4求x+y-z 已知x/4=y/5=z/6 求x+y+z/3x-2y+z的值 已知x/4=y/5=z/6,求x+y+z/3x-2y+z的值. 已知方程组2x-3y-4z=0和x+y+z=0,并且z≠0,求x：y与y：z 若X:Y:Z=5:6:7那么(Y-X):(Y+Z)和(X+2Y+3Z):(3X+2Y+Z) 已知4x-3y-6z=0,x+2y-7z=0,求5x+2y-z/2x-3y-10z 已知方程组{2x-3y+z=0 且x*y*z不等于0 求 x：y：z {3x-2y-6z=0 已知x^3+y^3-6x+2y+z+3+10=0,求（x-y+z)(x+y-z)的值.（z+3)是绝对值 已知x,y,z∈ R,x+2y=z+6,x-y=3-2z,求x^2+y^2+z^2的最小值. 已知有理数x、y、z满足条件|x-z-2|+(3x-6y-7)^2+|3y+3z-4|=0,求x、y、z 已知有理数x,y,z满足|x-z-2|+|3x-6y-7|+(3y+3z-40)^2=0,求x,y,z的值 已知X+Y/2=Y+Z/3=Z+X/4,且2X+4Y+6Z=120,求X,Y,Z的值