Question

A={x|x apartine n,x=2k+3,1< sau =k< sau =5}

Answer 1

K = {1,2,3,4,5}
inlocuim in relatia x = 2K+3 si avem:
k =1, x = 2*1 +3 = 5 
k = 2,x = 2*2 +3 = 7 
k =3 ,x = 2*3 + 3 = 9
k = 4,x = 2*4 + 3 =11
k = 5,x = 2* 5 + 3 = 13
⇒
A = { 5. 7 . 9 . 11  . 13 }