我有條數唔識?
(3X+7)(3X-7)
我有條數唔識?
2007-03-25 9:43 pm
回答 (6)
2007-03-27 6:15 am
(3X+7)(3X-7)
=3x÷2+7+2
=9x÷2+49
=3x÷2+7+2
=9x÷2+49
2007-03-26 3:19 am
(3x+7)(3x-7)
=(3x)^2-7^2
=9X^2-49
=(3x)^2-7^2
=9X^2-49
2007-03-26 2:17 am
1.) (3X+7)(3X-7) = 9x^2 - 21x +21x - 49 = 9x^2 - 49
2.) since (a+b)(a-b)= a^2 - b^2
(3X+7)(3X-7) so a is 3x and b is 7
(3X+7)(3X-7) = (3x)^2 - 7^2 = 9x^2 - 49
2.) since (a+b)(a-b)= a^2 - b^2
(3X+7)(3X-7) so a is 3x and b is 7
(3X+7)(3X-7) = (3x)^2 - 7^2 = 9x^2 - 49
參考: mE
2007-03-25 9:49 pm
=9x^2+49
收錄日期: 2021-05-02 13:49:15
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070325000051KK02116