Calculus problem help

So this is the function f(x)=(x+4)/(x^2+5x+4)
First thing to note is that f(x) = 1/(x+1), except at x = -4
Can anyone confirm that I got the right answers

1. Domain: All real nos except -4 and -1
Right.
2. Range:(-∞,-1/3)∪(-1/3,∞)
I don't believe 0 is part of the range.

3. For critical points I get x=-4 and x=-1 but since the function is not defined at these points so no critical points right?
Right.
4. The increasing/decreasing interval for the function will be decreasing entirely
Right.
5. At x=-4 the function wont be continuous but how am I supposed to show it in mathematical form

f(-4)=undefined
I would stop there...
limit(x approaches -4)=undefined
...because the limit exists as x approaches -4. It is -1/3.

so not continuous,is this the correct way?
In order for a function to be continuous at a point the value at the point has to equal the limit as the function approaches the point. When the function has no value at that point this cannot happen.

6. The inflection point I got was x=-1 but since again the function is also undefined at this point so there will be no inflection point
Right.
7. For concavity the function will have concave down decreasing from (-oo,-1) and concave up decreasing from (-1,+oo)
Right.