a,b,c满足a+b+c=0,abc>0 => a、b、c两负一正设 a<0, b<0, c>0. a+b = - c, ab < c^2 1/a+1/b+1/c = (a+b) / (ab) + 1/c = - c /(ab) + 1/c= (-c^2 + ab)/(abc) < 0
题目不全
