# Math Help - Proof by Condradiction

Glad I found this site. Here is my first post. I really am unsure of where to start all of this new material is confusing me. Please help.

1.
(a) Assume that n is a positive integer. Use the proof by contradiction method to prove:

If 7n + 4 is an even integer then n is an even integer.

2. Originally Posted by premierplayer
1.[/FONT](a) Assume that n is a positive integer. Use the proof by contradiction method to prove:
If 7n + 4 is an even integer then n is an even integer.
Assume that $7n+4$ is even and $n$ is odd.
Now an odd times an odd is odd. An odd plus an even is odd.
There is a contradiction in there somewhere. Can you find it?

3. Originally Posted by premierplayer
1.[/FONT](a) Assume that n is a positive integer. Use the proof by contradiction method to prove:
If 7n + 4 is an even integer then n is an even integer.
Assume that $7n+4$ is even and $n$ is odd.
Now an odd times an odd is odd. An odd plus an even is odd.
There is a contradiction in there somewhere. Can you find it?