Answer:
Step-by-step explanation:
Hello,
If n is even, it means that we can find k integer such that n = 2 * k.
Then n+1=2*k+1 is odd.
3n+1=6k+1=2*(3k)+1 where 3k is an integer so 3n+1 is odd.
3n = 2*(3k) is even.
Besides, if n+1 is odd we can find an integer p so that n+1=2p+1 so n = 2p is even.
3n+1 is odd means that we can find an integer q such that 3n+1=2q+1 so 3n=2q as 3 is not dividable by 2, it means that n is a multiple of 2, then n is even.
3n is even means that we can write 3n = 2z where z is an integer and again it means that n is a multiple of 2 and then n is even.
Thank you.
