Difference of 2 squares question?
回答 (3)
2018-04-11 9:00 pm
remember a^2 - b^2 = (a + b)(a - b)
hence 9x^2 - 1 = (3x + 1)(3x - 1) = (-3x + 1)(-3x - 1)
hence 9x^2 - 1 = (3x + 1)(3x - 1) = (-3x + 1)(-3x - 1)
2018-04-11 8:32 pm
Use the algebraic formula a^2-1^2 = (a+1)(a-1)
You can rewrite 9x^2 as (3x)^2, because (3x)^2 = 3^2 x^2 using algebraic formula (ab)^2 = a^2b^2.
Therefore, you can rewrite your problem as
9x^2-1 = (3x-1)(3x+1)
For the future if you every encounter something like 9x^2-2, you can rewrite it as (3x-sqrt2)(3x+sqrt2), where sqrt is square root
You can rewrite 9x^2 as (3x)^2, because (3x)^2 = 3^2 x^2 using algebraic formula (ab)^2 = a^2b^2.
Therefore, you can rewrite your problem as
9x^2-1 = (3x-1)(3x+1)
For the future if you every encounter something like 9x^2-2, you can rewrite it as (3x-sqrt2)(3x+sqrt2), where sqrt is square root
2018-04-11 8:16 pm
9x^2 =(3x)^2
1 = 1^2
a^2-b^2 = (a-b)(a+b)
(3x)^2 -(1)^2 = (3x-1)(3x+1)
1 = 1^2
a^2-b^2 = (a-b)(a+b)
(3x)^2 -(1)^2 = (3x-1)(3x+1)
收錄日期: 2021-04-24 01:04:48
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20180411121027AAB0MQ6