(1/2x+2/3y-3/4z)^2-(1/2x-2/3y-3/4z)^2,是因式分解呢【急!】

设x,y.z为实数,2x.3y.4z是等比数列,1/x,1/y.1/z是等差数列,则(x/z)+(z/x)是多少? 化简-(-3x-y+2z)-{-x+【4x-(x-y-z)-3x+2z} x+2y=3x+2z=4y+z 求x:y:z x+y/2=z+x/3=y+z/4 x+y+z=27 数学--整式运算4(x-y+z)-2(x+y-z)-3(-x-y-z) 求化简(x+3y+2z)(x-3y+6z)(x+3y+4z-2z)(x-3y+4z+2z) 4x+y+z=-3 2x+3y-4z=-10 x+2y-z=-1 x+y+z=2 4x+2y+z=4 2x+3y+z=1 x-y-z=1 2x+y-3z=4 3x-2y-z=-1 x+y-z=6 x-3y+2z=1 3x+2y-z=4 阿 x+y-z=6,x-3y+2z=1,3x+2y-z=4 x+y+z=-5,3x+y+z=1,4x+3y+2z=-2快 3x+2y+z=4 x+y+z=10 2x+3y-z=1 x+y-z=6 x-3y+2z=1 3x+2y-z=4 3X+Y+Z=0,2X-Y+3Z=1,X+2Y-Z=4 3x-y+2z=-1 4x+y+z=5 x-2y-z=-2 x-y+z=-1 5x+2y-z=6 4x-3y+2z=-5 x+y+z=-1 4x-2y+3z=5 y-z=8-2x