(1 point)
NOTE: When using interval notation in WeBWorK, remember that:
You use 'INF' for \( \infty \) and '-INF' for \( -\infty \).
And use ' \( U \) ' for the union symbol.
Enter DNE if an answer does not exist.
\[
f(x)=\frac{x}{x^{2}+12 x+35}
\]
a) Give the domain of \( f \) (in interval notation) \( \square \)
b) Find the critical numbers of \( f \). \( \square \) II (Separate multiple answers by commas.)
c) Determine the intervals on which \( f \) is increasing and decreasing.
\( f \) is increasing on: \( \square \)
\( f \) is decreasing on: \( \square \)
d) Use the First Derivative Test to determine whether each critical point is a relative maximum, minimum, or neither.
Relative maxima occur at \( X= \) \( \square \) (Separate multiple answers by commas.)
Relative minima occur at \( X= \) \( \square \) (Separate multiple answers by commas.)
