Decreasing?  Pierre is walking downhill...
 


 

f is decreasing on.


How about this one?


 


 

It's one wild ride for Pierre!  Downhill sledding all the way!  But, if we said that f is decreasing everywhere, that wouldn't be quite right...  Because the graph doesn't exist at x = -4 and at x = 2.

It's decreasing everywhere on its own domain, which is