题目应为:xy/(x+y)=6/5 yz/(y+z)=12/7 xz/(x+z)=4/3 求x和y和z 运用倒数变形可解因为1/y+1/x=5/6,1/z+1/y=7/12,1/z+1/x=3/4三式相加得1/x+1/y+1/z=13/12所以1/z=1/4,1/x=1/2,1/y=1/3所以x=2,y=3,z=4...