Hi, may I know how to solve this question? Thank you!
Question
5^{n+1} + 2(5^{n-1}) = 135
Answer
Hi Jane,
For this question, we want to find n. Because n here is a power, what we can do is rewrite the equation such that we can find 5^n first. We will split 5^{n+1} into 5 \times 5^n, and 5^{n-1} into \frac{5^n}{5}, so that we can factorize out the 5^n :
Here, it should be clear that our answer is n=2, but just to be extra thorough, we can use logarithms to justify our answer.
Hope this helps! 
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Got it, thank you so much!
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