How would I work this astronomy problem?

[Bernie mac]

An asteroid has a perihelion distance of 3.0 AU and an aphelion distance of 5.0 AU Calculate its orbital semi-major axis, eccentricity, and period.
semi-major axis
_______ AU
eccentricity
_________
period
________ years

 

[starryskyn]

I guess you should work it by yourself since this is homework and learning is minimal if we do it for you.