In the attached picture you have the graph of [tex]y=e^x[/tex]. To evaluate the function at [tex]x=0[/tex], you'll have to start from 0 on the x axis, and travel vertically until you meet the graph.
In this case, if you start from the origin, you have to go upwards one unit, until you meet the graph at (0,1).
So, if [tex]x=0[/tex], [tex]y=1[/tex].
