I'm not going to graph these, you should be able to do that yourself. However I will note that only two of these graphs are the same. The trick is in the last graph: and are "apparently" the same since each reduces to x, but note that in the first expression the domain is and in the last second expression is .
and aren't the same either since only returns a positive value. It is for this very reason that and have the same graph.
Depends on which "mirror" you are talking about. The typical mirror "planes" are the x and y axes, and the lines y = x and y = -x.
y = x reflected over the x-axis is y = -x.
y = x reflected over the y-axis is y = -x.
y = x reflected over the line y = x is y = x.
y = x reflected over the line y = -x is y = x.
-Dan