3 -4 2 0
0 0 0 0
0 0 0 0
x2 = free
x3 = free
x1 = ?
收錄日期: 2021-04-25 17:17:44
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071125000051KK02058