i am going to my dad's in michigan this summer and i was wondering if i can bring a shaving razor in a bag that i check in
Yes, no problem. You can even take it in your carry-on, if you want to.
What kind of razor is it?
I'm assuming that it's not an old fashioned style straight razor (with a long blade)?
That may be the one exception to Kent's reply.
If its checked luggage its okay for sure. It's probably okay in carry on as well.