xy／x+y＝1,yz／y＋z＝2,xz／x＋z＝3求x,y

xy/(x+y)=1,取倒数(x+y)/xy=1x/xy+y/xy=11/y+1/x=1.1yz/(y+z)=2,取倒数(y+z)/yz=1/2y/yz+z/yz=1/21/z+1/y=1/2.2xz/(x+z)=3取倒数(x+z)/xz=1/3x/xz+z/xz=1/31/z+1/x=1/3.31式+2式+3式得2(1/x+1/y+1/z)=1+1/2+1/32(1/x...