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The questions im working on is..

$ \left(2^\left(n+3\right) - 2^n\right)/14 $

My thought process behind solving it was to spilt the first 2 term into two separate terms then cancelling the 2^n leaving 2^3 over 14

$ (2^n \cdot 2^3-2^n)/14 $


$ (2^3)/14 = 8/14 $


however this is incorrect, how am i supposed to correctly simplify this equation?

Sorry about messing up the formatting so much

M.Mass
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S.Ban
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2 Answers2

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Are you having trouble simplifying this fraction? Well, you have failed to see that you can factor out $2^n$ from the expression in the numerator. What you did there is an incorrect piece of mathematics. Memorize this fact: $ab \pm a=a(b \pm 1)$. The idea here is that if each term in an expression shares a common factor, you can bring it out front. Once you've factored out the $2^n$, the rest is pretty straightforward. Here's how it typically would be done:

$$ \frac{2^{n+3}-2^n}{14}= \frac{2^n\cdot 2^3 - 2^n}{14}= \frac{2^n(2^3 - 1)}{14}= \frac{2^n(8-1)}{14}= \frac{2^n \cdot 7}{14}= \frac{2^n}{2}= 2^n \cdot 2^{-1}= 2^{n-1} $$

And that's as far as you can go in terms of simplification.

Michael Rybkin
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Steps:

$2^{n+3}= 2^n2^3= 2^n×8.$

$(2^{n+3} -2^n) = 2^n(8-1)=7×2^n.$

$14=2×7$.

$\dfrac{7×2^n}{14}= 2^n/2^1= 2^{n-1}.$

Peter Szilas
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