1. 81x*2+90xy+25y*2
2. 81(m-n)*2+90(m-n)(p+q)+25(p+q)*2
收錄日期: 2021-04-20 19:32:32
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070414000051KK02184