Set M = {XIX = 2K + 1, K ∈ Z}, n = {XIX = 4K ± 1, K ∈ Z} How to prove n ∈ m? It is said in the book that n ∈ M can be explained in detail because m is an odd number set

Set M = {XIX = 2K + 1, K ∈ Z}, n = {XIX = 4K ± 1, K ∈ Z} How to prove n ∈ m? It is said in the book that n ∈ M can be explained in detail because m is an odd number set

Let 2K be a variable. When m = 4k-1, that is, M = 2 (2k-1) + 1, M is odd. When m = 4K + 1, that is, M = 2 (2k) + 1, so m is odd. To sum up, M is all odd, so n is included in M