Question

C={x/x€N,x=2k+1, k mai mic sau egal cu 4, k€N}

Answer 1

k = {0,1,2,3}
x=2*0+1
x=0+1
x=1

x=2*1+1
x=2+1
x=3

x=2*2+1
x=4+1
x=5

x=2*3+1
x=6+1
x=7

x∈{1,3,5,7}