The optics of lenses?

Question

Where must the object be placed to have a virtual erect image?

Where must the object be placed in order to have an inverted image on the opposite side of the lens to the object?


Imagine a diagram, but I truly am stumped on these two...one could be focal point, but I am guessing, any help out there?

Answer 1

see:
http://en.wikipedia.org/wiki/Thin_lens
http://en.wikipedia.org/wiki/Lens_%28optics%29