1.因式分解:
(a+b)2次方-(2a-b)2次方
2.若a:b=1.5:2和b:c=3分之2:4分之1。求a:b:c。
我有兩條Math不懂??
2009-01-10 5:34 am
回答 (2)
2009-01-10 6:10 am
✔ 最佳答案
1) (a+b)^2-(2a-b)^2=a^2+b^2-4a^2+b^2
=-3a^2+b^2
2) a:b=1.5,2 &b:c=2/3:1/4
a:b:c=1:4/3:1/2
參考: ME.
2009-01-10 6:22 am
1. (a+b)^2 - (2a-b)^2
= [a^2 + 2ab + b^2] - [4a^2 - 4ab + b^2]
= -3a^2 + 6ab
= -3a(a - 2b)
2.
a : b = 1.5 : 2 = 3 : 4 = 6 : 8
b : c = 2/3 : 1/4 = 8 : 3
a : b : c = 6 : 8 : 3
= [a^2 + 2ab + b^2] - [4a^2 - 4ab + b^2]
= -3a^2 + 6ab
= -3a(a - 2b)
2.
a : b = 1.5 : 2 = 3 : 4 = 6 : 8
b : c = 2/3 : 1/4 = 8 : 3
a : b : c = 6 : 8 : 3
參考: ME
收錄日期: 2021-04-19 13:21:03
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090109000051KK01610