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# I need help with this:

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1. Given $$m\geq 2$$, denote by $$b^{-1}$$ the inverse of $$b\pmod{m}$$. That is, $$b^{-1}$$ is the residue for which $$bb^{-1}\equiv 1\pmod{m}$$. Sadie wonders if $$(a+b)^{-1}$$ is always congruent to $$a^{-1}+b^{-1}$$ (modulo $m$). She tries the example a=2, b=3, and m=7. Let L be the residue of $$(2+3)^{-1}\pmod{7}$$, and let R be the residue of $$2^{-1}+3^{-1}\pmod{7}$$, where L and R are integers from 0 to 6 (inclusive). Find L-R.

May 26, 2020

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https://web2.0calc.com/questions/help_19751

May 26, 2020
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That's not helpful unfortunately, nobody provided an explanation to that post.

May 26, 2020