2/5+1/3a=1/5
a -15
b -3/5
c -9a^9+12a
d 7a+12
收錄日期: 2021-04-21 17:00:14
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20160221102743AAXDHUl