please help very confusing

Yep...confusing !!!

Note that   g(x) = 3    can be considered  as the line  y = 3

So....note that   any x value on this line will have the associated y value of 3

So.....for example.....the points  (-1, 3)  (0, 3)  (1, 3) ( 2, 3)  (3, 3) etc. are all on the line

So   g(2)  is really the  point (2, 3)

So  g(2)  =  3

Hope that makes some sense  !!!

Another way to see this is to write  g(x) in a slightly different manner....

g(x) = 3x^0

So

g(2) =

3 (2)^0 =  

3   ..... !!!