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# help plz

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Let n be a positive integer greater than or equal to 3 . Let a,b be integers such that  ab is invertible modulo n  and $$(ab)^{-1}\equiv 2\pmod n$$. Given a+b is invertible, what is the remainder when $$(a+b)^{-1}(a^{-1}+b^{-1})$$ is divided by n?

Apr 15, 2021

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$$(a+b)^{-1}(a^{-1}+b^{-1})=\frac{1}{ab}$$

the question has already told you that the remainder will be 2 when it is divided by n.

That is what mod means

mod means remainder.

Apr 18, 2021