30: D( f ) = ℝ; f is continuous there.

y-intercept: f (0) = 4; x-intercepts:

f is not symmetric, see f = 0.
Limits at endpoints:

Interpretation as asymptotes:
No horizontal asymptote at −∞, but a chance for oblique.

So no oblique there.
No horizontal asymptote at ∞, but a chance for oblique.

So no oblique there.

Now determine monotonicity using f ′.

Next hint
Answer