23: The domain is D( f ) = (−∞,−1) ∪ (−1,∞).
The derivative is

Critical points: The equation f ′(x) = 0 has solution x = 0.
There are no points in D( f ) where the derivative does not exist.

Intervals of monotonicity will be (−∞,−1), (−1,0], and [0,∞). Determine monotonicity and local extrema using a chart.

Next hint
Answer