Functions-Domains,Ranges and Subsets.

[Demoniac]

Homework Statement

Can you please explain in as much detail as possible the two following problems?
1.Each set is a function from set A to set B. a.What is the largest subset of the real numbers that can be set A, the domain of the given function? b. If set A=set B, is the function onto? Justify your answer. The problem is {x,y):y=5-x}.

2.For the next problem I can't actually show you the graph but I have to determine if the graph represents a function and I have to state the domains and ranges. How would I do this on a graph?

And what exactly is a subset?

Homework Equations

None.

The Attempt at a Solution

I couldn't even seem to wrap my head around the problem. I just couldn't figure it out. I stared at it for about an hour and I still couldn't understand it.

 

[Outlined]

Do a Wikipedia on what a subset and a function is.