Question

4n+7:2n-1 apartine lui z​

Answer 1

(4n+7)/(2n-1) = [2(2n-1)+9]/(2n-1) =

= 2 + 9/(2n-1)

2n-1 ∈ D₉  ⇔  2n-1 ∈ {-9; -3; -1; 1; 3; 9}⏐+1

⇔  2n ∈ {-8; -2; 0; 2; 4; 10}⏐: 2

⇔  n ∈ {-4; -1; 0; 1; 2; 5}