望采纳
1/a +1/b +1/c=-2(a+b)/(ab)+ (b+c)/(bc)+ (c+a)/(ac)=1/a +1/b +1/b +1/c +1/c +1/a=2(1/a +1/b +1/c)=2·(-2)=-4
如图
是-4吧
