Maths
1a) Factorize 8a^3 - 1
b) Hence, factorize 8x^3 - 6x + 2
( Hint: Convert 8x^3 - 6x + 2 into the sum of two polynomials , one of which is 8x^3 - 1 )
English
1. For a year now , Mr.Harris ..... charity balls to collect money for the homesless.
a) had been organizing
b) was organizing
c) would be organizing
d) organized
e) has been organizing
Maths and English
2013-09-29 8:38 pm
回答 (2)
2013-09-29 9:21 pm
✔ 最佳答案
Maths.1a) 8a³-1
=(2a)³-1³
=(2a-1)[(2a)²+(2a)(1)+1²]
=(2a-1)(4a²+2a+1)
1b) 8x³-6x+2
(8x³-1)+(-6x+3)
=(2x-1)(4x²+2x+1)-3(2x-1)
=(2x-1)(4x²+2x+1-3)
=(2x-1)(4x²+2x-2)
=(2x-1)(2x-1)(2x+2)
=(2x-1)²(2x+2)
Eng. 1. ans: e 因為今年已經完成, 所以用present perfect tense,
present perfect tense 的形態是：
have / has + 動詞的過去分詞
可參考:
http://www.npc.edu.hk/staff/~ngtungying/english_grammar/lessons/lesson22.htm
收錄日期: 2021-04-20 14:19:47
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20130929000051KK00087