2x+3y+4z,xyz

x:y:z=2:3:4且x+y+z=18求xyz 化简3X^2y-{xyz-(2xyz-9x^2z+4x^2z)+[3x^2y+(4xyz-5x^2z-3xyz)]}等于 方程组:x-2y+4z=0,2x+3y-3z=0...xyz不等于0,求(2x+y-z)\(2x-y+z) 已知4x-3y+z=0,x+2y-8z=0,xyz不等于0,求x+y-z/x-y+2z的值 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 先化简再求值3xyz+2(x^2y+y^2z-xyz)-xyz+2z^2x x=1 y= -1 z=2 3x的2次方*y-{xyz-(2xyz-y的2次方*z)-4y的2次方*z+[3x的2次方-(4xyz-5y的2次方*z 已知xyz满足x+y+z=30,3x+y-z=50,设t=5x+4y+2z 1当t=40时,求xyz的值 2若xyz均为 XYZ满足XY/X+Y=-2,YZ/Y+Z=3/4,ZX/Z+X=-4/3,求XYZ/XY+YZ+ZX的值 已知XYZ满足／x-2-z／+（3x-6y-7）²+／3y+3z-4／＝0.求XYZ的值 已知有理数xyz 满足|x-z-2|+（3x-6y-7)的二次方+|3y+3z-4|=0 ,求xyz的值. 若 x/2等于y/3等于z/4,且x+y-z=5 求xyz的值