You can put this solution on YOUR website!
Now pick a few values for y and solve for x. Usually you pick an x and solve for y, but in this case, I think it is easier to go the other way.
y=0 = 3^0 = 1 --> x=1
y=1 = 3^1 = 3 --> x=3
y=2 --> x=9
y=-1 --> x = 1/3
Plot those points and draw in the smooth curve that connects them.
The plot is show at the URL below.
This site can help you with this type of problem -->http://www55.wolframalpha.com/input/?i=y%3Dlog3(x)