3y2 - 12xy + 12x2
= 3[y2 - 4xy + 4x2]
= 2[(y)2 - 2(y)(2x) + (2x)2]
= 2(y - 2x)2
為什麼到了步驟3時:
= 3[y2 - 4xy + 4x2]
= 2[(y)2 - 2(y)(2x) + (2x)2]
3會變了2?
收錄日期: 2021-04-20 22:14:36
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090530000051KK00970