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generally expo factoring

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Master | Next Rank: 500 Posts
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by smallsorrow » Tue Oct 14, 2008 11:51 pm
I know this might be annyoing... but I have a question which no book so far could answer:
There is a factoring "trick", which is e.g.
2^(x)+2^(x-1) = 2^x-2 (2^2+1) - can anybody explain the rule behind this?
Thank you very much!!
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by stop@800 » Wed Oct 15, 2008 12:12 am
No logic required, you just need to take out common part :)

2^x + 2^(x-1)

4 * (2^(x-2)) + 2 * (2^(x-2))

2^(x-2) [4 + 2]

Please see if you have made any typo

The answer should be
2^x-2 (2^2+2)
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by raunekk » Wed Oct 15, 2008 1:04 am
i agree with stop@800,,,

there should be 2 in place of 1
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by smallsorrow » Wed Oct 15, 2008 7:11 am
me and the typos - you are right its a 2
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hey i feel like a retard

by ehimare » Thu Oct 16, 2008 3:12 am
can you explain this step

2^x + 2^(x-1)

4 * (2^(x-2)) + 2 * (2^(x-2))
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