Suppose that $$f(x) = \frac{3 x - 5}{x + 3}.$$
(A) Use interval notation to indicate where $f(x)$ is concave up.
Note: When using interval notation in WeBWorK, you use I for $\infty$, -I for $-\infty$, and U for the union symbol. If there are no values that satisfy the required condition, then enter "{}" without the quotation marks.

Concave up:

(B) Use interval notation to indicate where $f(x)$ is concave down.
Concave down:

(C) Find all horizontal asymptotes of $f$. If there are no horizontal asymptotes, enter -1000. If there are more than one, enter them separated by commas.
Horizontal asymptote(s): $y$ =

(D) Find all vertical asymptotes of $f$. If there are no vertical asymptotes, enter -1000. If there are more than one, enter them separated by commas.
Vertical asymptote(s): $x$ =