9x^2-4 factorise please?

2009-07-30 11:16 am

回答 (9)

2009-07-30 11:43 am

✔ 最佳答案

9x² - 4 = 0
9x² = 4
x² = 4/9
x = ± 2/3

= x - 2/3, = 3x - 2
= x + 2/3, = 3x + 2

Answer: (3x - 2)(3x + 2)

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2009-07-30 11:27 am

(3x+2)(3x-2)

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2009-07-30 11:22 am

Difference of squares, with a being 3x and b being 2. Fits right into the formula (a+b)(a-b).

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2009-07-31 7:21 pm

( 3 x - 2 ) ( 3 x + 2 )

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2009-07-30 12:42 pm

a^2 - b^2 ≡ (a + b)(a - b)

9x^2 - 4
= (3x)^2 - 2^2
= (3x + 2)(3x - 2)

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2009-07-30 12:14 pm

Difference of two squares:
a² - b² = (a + b)(a - b)

9x² - 4
(3x)² - 2²
(3x + 2)(3x - 2)

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2009-07-30 11:44 am

Difference of squares.

x²-y² = (x-y)(x+y)

9x²-4 = (3x-2)(3x+2)

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2009-07-30 11:28 am

9x^2-4 = (3x)^2-2^2
= (3x+2)(3x-2) note that a^2-b^2=(a+b)*(a-b)

參考: This is all about basic mathematics. Thank You

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2009-07-30 11:24 am

9x^2-4
=9x^-6x+6x-4
=3x(x-2)+3(x-2)
=(x-2)(3x+3)
so (x-2)(3x+3)are the factors of 9x^2-4

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