20: D( f ) = (−∞,0) ∪ (0,∞); f is continuous there.
y-intercept: f (0) not possible; x-intercepts: f = 0 not possible.
f is not symmetric since f (−x) is not equal to f (x) nor to -f (x) (try e.g. x = 1).
Limits at endpoints:

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

Asymptote y = x + 2 there.
Vertical asymptote at x = 0.
No horizontal asymptote at ∞, but a chance for oblique.

Asymptote y = x + 2 there.

Now determine monotonicity using f ′.

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Answer