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Math Help - Subtracting exponents with the same base

  1. #1
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    Subtracting exponents with the same base

    Hey everyone,

    A small queston

    2^(k+1) - 2^k

    How did they get 2^k (2-1)??

    thank you
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  2. #2
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    Quote Originally Posted by Thetheorycase View Post
    Hey everyone,

    A small queston

    2^(k+1) - 2^k

    How did they get 2^k (2-1)??

    thank you
    A common factor is 2^{k} since 2^{k+1} = 2^k \cdot 2^1 = 2^k \cdot 2 using the well known index law.

    Therefore: 2^{k+1} - 2^k = 2^k (2 - 1).
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  3. #3
    Senior Member Shanks's Avatar
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    observe that
    2^{k+1}=2\times 2^k.
    now can you continue from here?
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