一般一元五次(及以上)方程无求根公式的直观解释(转)
http://www.360doc.com/content/24/0609/10/99071_1125725480.shtml
https://viegg.com/abel/readme.html
https://www.zhihu.com/question/29316970/answer/151839928
https://www.zhihu.com/question/534514417
https://zhuanlan.zhihu.com/p/77583443
