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How do you factor 3x^3-192?

I thought you would just take out the 3 and make it 3(x^3-64) but then I remembered these are the ones that would be 3(    )(     ) but I cannot get my answer into that form.
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1 Answer

3x^3 - 192
 
Factor out the 3:
 
3(x^3 - 64)
 
 
Since x^3 - 64 is a difference of two cubes, 
 
(a^3 - b^3) = (a - b) (a^2 + ab + b^2),
 
and a = x and b = 4:
 
 
 
3(x - 4)(x^2 + 4x + 16)
 
Check:
3(x^3 + 4x^2 + 16x - 4x^2 - 16x - 64)
 
 
Hope this helps.
Jason

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