So as x, let me do this in a color you can see, as x approaches six from both sides, well as we approach six from the left-hand side, from values less than six, it looks like our f of x is approaching one, and as we approach x equals six from the right-hand side, it looks like our f of x is once again approaching one. And in order for this limit to exist, we need to be approaching the same value from both the left and the right-hand side. And so here, at least graphically, so you never are sure with the graph, but this is a pretty good estimate, it looks like we are approaching one. Right over there, let me do it in a darker color. Now let's do this next one. The limit of f of x as x approaches four. So as we approach four from the left-hand side, what is going on?