Question

A={n apartine N / n+7 supra n+1 apartine N}

Answer 1

n+1I n+7
n+1I n+1+6
n+1I6
n+1=1   n=0
n+1=2   n=1
n+1=3   n=2
n+1=6   n=5

A={0,1,2,5}