Lvl 7 with 12
 

can a lvl 7 get exp with a 12?

yes

no

The highest you can group with is either level/2 above you, or +5 levels, whichever is greater.

So yeah, 7 and 12 should work.

Ooh, I didn't know about the +5 clause, I guess because it stops being a thing after level 10.

(your level) X (1.5) = highest you can group with

http://www.youtube.com/watch?v=-qYji0HQ5CY

Group up. Kill something. If the lower level person gets experience, then they can get experience.

another variable to keep in mind: if the mobs are too low for the lvl 12 to get exp from, then no exp for the lvl 7 either.