I usually don't do people's homework for them, but this time I couldn't resist.
1. (x + y) / (m + 2n)
2. -1 / (x + 2)
3. 0
4. 1
5. (x + 2) / (3x + 2)
I haven't taken a math class in four years, (stupid Television-Radio major, heheh), so I always jump at the chance to do some math problems. Like an itch I've got to scratch.