F.3 Factorize
回答 (1)
2010-09-07 1:53 am
✔ 最佳答案
28(x+y)^2 - 7(x-y)^2= 7[ 4(x+y)^2 - (x-y)^2 ]
= 7{ [2(x+y)]^2 - (x-y)^2 }
= 7{ [(2(x+y) + (x-y)] [2(x+y) - (x-y)] }
= 7 (2x+2y+x-y) (2x+2y-x+y)
= 7 (3x+y) (x +3y)
收錄日期: 2021-04-21 22:14:47
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100906000051KK00863