What is (3x + 1)(3x - 1)?
回答 (10)
2009-11-23 2:53 pm
✔ 最佳答案
(3x + 1)(3x - 1)= 3x(3x) - 3x(1) + 1(3x) - 1(1)
= 9x^2 - 3x + 3x - 1
= 9x^2 - 1
2009-11-27 12:33 am
9 x ² - 3x + 3x - 1 = 9 x ² - 1
2009-11-23 10:58 pm
9x^2-3x+3x-1^2 = 9x^2-1
2009-11-23 10:50 pm
FOIL ... Yay!
First (3x)(3x) = 9x^2
Outside (3x)(-1) = -3x
Inside (1)(3x) = 3x
Last (1)(-1) = -1
so,
9x^2 - 3x + 3x - 1
9x^2 - 1
First (3x)(3x) = 9x^2
Outside (3x)(-1) = -3x
Inside (1)(3x) = 3x
Last (1)(-1) = -1
so,
9x^2 - 3x + 3x - 1
9x^2 - 1
2009-11-23 10:49 pm
9x^2 + 3x - 3x - 1
Simplify
9x^2 -1
When you have the same in both parts with a different sign you'll usually loose the middle.
Simplify
9x^2 -1
When you have the same in both parts with a different sign you'll usually loose the middle.
2009-11-23 10:49 pm
(3x+1)(3x-1) = (9x2 -3x + 3x -1) = 9x2 - 1
The -3x and +3x cancel each other out.
The -3x and +3x cancel each other out.
參考: My brain
2009-11-23 10:48 pm
3x+3x=9x^2
1*3x=3x
1*-3x=-3x
1*-1=-1
9x^2-1
1*3x=3x
1*-3x=-3x
1*-1=-1
9x^2-1
2009-11-23 10:47 pm
(3x + 1)(3x - 1)
= (3x*3x) - (3x*1) +(1*3x) -1
= 9x^2 - 1
= (3x*3x) - (3x*1) +(1*3x) -1
= 9x^2 - 1
2009-11-23 10:46 pm
9x^2 - 1
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