Answer:

To show that (x-1 )is a factor of( x^n-1)

Let p(x)=x^n−1

In order to show that (x−1) is a factor of (x^n −1), it is sufficient to show that p(1)=0.

Now, p(x)=x ^n−1∴p(1)=1^ n −1=1−1=0

∴(x−1) is a factor of (x ^n −1)

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