Question

if n is an odd positive integer then n^2-1 is always divisible by? 1) 6 2) 10 3)8
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Answer 1

Answer

Let n be a positive integer and b=4

By Euclid division lemma n=bq+r

and r is less than b and equal or greater than 0

if r=4

Then

n=4q+r

n^2=(4q+r)^2

It is divisible by 8