Prove that 6^n - 1 is divisible by 5 for all positive integers n.
I can't prove it with mathematic symbols and stuff, but I can prove it with words.
No matter how many times you multiply 6 by itself, the product will always end with a 6.
When you subtract 1, the number ends with a 5. Any number that ends with a 5 is divisible by 5.
Is that good enough?
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