1) rs + 2r +s + 2
2) -9f ^2+3f +2
3) 4m ^2+mn - 3n ^2
4) x^2/4 + 2x +1
收錄日期: 2021-04-23 23:24:55
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100105000051KK01694