Answer:
The arrow in each end of the function means continuations. Remember that, decreasing is when x increases while y decreases. And increasing is when x increases while y increases.
Left end:
As x decreases without bound, the graph of f(x) approaches y = 0, because in the graph we can see that there's sort of restriction on x-axis.
Right end:
As x increases without bound, the graph of f(x) increases without bound. Because the graph doesn't show any kind of restriction at the right end.