Showing a function f is continous on R^n and f(x) = c.x is continus on R^n confused!

[voidflux]

Hello everyone, i'm so lost on these 2 questions...they are:
http://img437.imageshack.us/img437/5193/q30pi.jpg
if that link sucks try this one:
http://show.imagehosting.us/show/789..._-1_789841.jpg

Question 2:
http://img437.imageshack.us/img437/8540/q47ni.jpg
mirrior:
http://show.imagehosting.us/show/789..._-1_789846.jpg

I know a function f of two variables is called continuous at (a,b) if
lim (x,y)->(a,b) f(x,y) = f(a,b);
We say f is continous on D if f is continuous at every point (a,b) in D.

Also If f is defined on a subset D of R^n, then lim x->a f(x) = L means that for every number E > 0 there is a corresponding number delta > 0 such that |f(x)-L| < E wherever x is a subset of D and 0 < |x-a| < delta. But i'm so lost on how i'm suppose to even start these 2. thanks.
Note: the BoLDED variables means they are vectors. and E is suppose to be epsalon or however u spell it

[jemidiah]

I have that exact definition in my own calc book. No sane teachers ever use them, to be honest.

Wish I could help more except that those pictures don't work. The first link's dead, and the second one has and ellipses in it

R^n is actually the number of dimensions you're using, as I remember, though from your previous post it looks like you've got a better grasp of that junk than I do. The rest of the notation is set-babble that I've never learned. Sorry