已知x+y/3=y-3z/2=x+3z/5且x+y+z=14则2x+3y-5z=

已知2x+5y+4z=15.7x+y+3z=14 则x+y+z=? x/2=y/3=z/5 x+3y-z/x-3y+z 已知3x-2y-5z=0,2x-5y+4z=0,且x,y,z均不为0,求3x*x+2y*y+5z*z/5x*x+y*y- 已知3x-2y-5z=0,2x-5y+4z=0,且x,y,z都不为0,求（3x*x+y*y+4z*z）/（5x*x+y* 已知方程组4x-5y+2z=0 x+2y=3z 则x:y:z thank you已知x+3y+5z=0,2x+3y+z=0 且x、y、z.都不是0,则（2y-z）（2y+z）除以z的 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) 已知x-y+z=0,3x+y-5z=0,则x+y+z/x+2y-3z=? 已知x-y+z=0.3x+y-5z=0,则x+y+z/x+2y-3z=_______ 已知方程组4x-y+3z=0 2x+y+6z=0且xyz不等于0,则x/y+y/z+z/x是多少 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x:y:z=2:3:4,且x-y+z=36,求x+y+z的值.