Question

A={x £ N|(x+1)£D12},B={x£N|x=2k +1,k £ N*,x £ A}.Aflati A n B,B-A

Answer 1

x+1 ∈ D12⇒ x+1∈ {1,2,3,4,6,12}⇒ x∈{0,1,2,3,5,11}⇒ A= {0,1,2,3,5,11}
2*0+1=1
2*1+1=3
2*2+1=5
2*3+1=7
2*5+1=11
2*11+1=23
B= {1,3,5,7,11,23}
A n B= {1,3,5,11}
B-A= {7,23}