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Factor 9x^2 - 64.

 Jun 29, 2020
 #1
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(3x - 8)(3x+8)

 
 Jun 29, 2020
 #2
avatar+8205 
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\(a^2 - b^2 = (a - b)(a + b)\).

 

By Law of indices, \(9x^2 = 3^2 x^2 = (3x)^2\), and \(64 = 8^2\).

 

We use the formula and substitute a = 3x, b = 8.

 

\(9x^2 - 64 = (3x)^2 - 8^2 = (3x - 8)(3x +8)\)

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 Jun 29, 2020

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