Hi,

 

Look,

 

Now,

1.   Lateral inversion means " If your image is laterally inverted, it means that your image's left is your right and your right is image's left ".

 

2.   For reversal of z-axis, i ams sorry , i don't know.

3.   Plane mirror is a straight plane surface. It can be considered to be a part of a very big sphere. That is, radius of curvature can be considered to be infinity. Now, for mirror it is well known that focal length is half of radius of curvature.

As, radius of curvature is infinity, focal length is also infinity.