What can you conclude about AC in the following? as in x < AC < x

1. BC = 7; AC = 2 + AB

2. AB + AC = 5; AC + BC = 4

3. BC + AC = 22; AB + BC = 12

Been working on this all day I just can't seem to figure it out, and no one seems to be able to explain it to me

Sorry if this is posted in the wrong forum, I couldn't tell if this belonged in Algebra or Geometry.