expand the following quection;
1.(a+b)(2a-1)
2.(x+y+1)(x-y)
help! hoe to do
2008-10-26 10:29 pm
回答 (2)
2008-10-26 11:54 pm
✔ 最佳答案
1. (a+b)(2a-1)=(a)(2a-1)+(b)(2a-1)
=2a^2-a+2ab-b
2. (x+y+1)(x-y)
=x^2+xy+x-xy-y^2-y +xy-xy約左
=x^2-y^2-x-y
2008-10-26 15:55:09 補充：
=x^2-y^2+x-y @@"
參考: F.5 用中5既頭腦諗既@@
2008-10-26 10:45 pm
1.(a+b)(2a-1）
=(a)(2a-1)+(b)(2a-1）
=2a^2-a+2ab-b
2.(x+y+1)(x-y)
=(x)(x+y+1)+(-y)(x+y+1)
=x^2+xy+x-xy-y^2-y
=x^2-y^2+x-y
2008-10-26 14:47:40 補充：
=2a^2-a+2ab-b
=2a^2+2ab-a-b
=(a)(2a-1)+(b)(2a-1）
=2a^2-a+2ab-b
2.(x+y+1)(x-y)
=(x)(x+y+1)+(-y)(x+y+1)
=x^2+xy+x-xy-y^2-y
=x^2-y^2+x-y
2008-10-26 14:47:40 補充：
=2a^2-a+2ab-b
=2a^2+2ab-a-b
收錄日期: 2021-04-29 16:15:52
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20081026000051KK01139