plz help me to answer the queston,if you do not know the answer,plz answer no!or you can change the question to chinese for me~thz for your help~
1.Given a and c are the tens and units gidits of a number while b and c are the tens and units digits of another number.Prove that when a+b=10,(10a+c)x(10b+c)=100(ab+c)+c^2.
F.2 mathz help plz
2007-09-17 12:00 am
回答 (2)
2007-09-17 12:18 am
✔ 最佳答案
Since a+b=10, then a=10-b.LHS= (10(10-b)+c)(10b+c)=1000b-100b^2+100c+c^2
RHS=100((10-b)b+c)+c^2=1000b-100b^2+100c+c^2
Therefore, LHS=RHS.
2007-09-17 12:09 am
(10a+c) x (10b+c)
= 100ab + 10ac +10bc + c^2
= 100ab + 10c (a+b) + c^2 [ Sub a+b = 10 ]
= 100ab + 100c + c^2
= 100 (ab + c) + c^2
= 100ab + 10ac +10bc + c^2
= 100ab + 10c (a+b) + c^2 [ Sub a+b = 10 ]
= 100ab + 100c + c^2
= 100 (ab + c) + c^2
參考: myself
收錄日期: 2021-04-13 13:31:48
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070916000051KK02956