Question

Prove that 41 is congruent to 21 (mod 3). Explain using words, symbols, as you wish

Answer 1

From the proof of modular congruence below, it has been shown that;

41 ≡ 21 (mod 3).

How to Solve Modular Arithmetic?

We want to use the definition of modular congruence to prove that;

41 is congruent to 21 (mod 3) i.e if a ≡ b (mod m) then b ≡ a (mod m).

We are trying to prove that modular congruence mod 3 is a symmetric relation on the integers.

First, if we recall the definition of modular congruence:

For integers a, b and positive integer m,  

a ≡ b (mod m) if and only if m|a–b

Suppose 41 ≡ 21 (mod 3).

Then, by definition, 3|41–21, so there is an integer k such that 41 – 21 = 3k.

Thus;

–(41 – 21) = –3k

So

21 – 41 = 3(–k)

This shows that 3|21 – 41.

Thus;

21 ≡ 41 (mod 3) and the proof is complete

Read more about Modular Arithmetic at; brainly.com/question/16032865

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