37 . B
Just plug in the six possible values for k, compute the results, and add them up:38 . C
The function is cubing. Think about each answer choice. (A): The cube of minus x equals the
cube of x? No. (B): The cube of minus x equals the opposite of the cube of minus x? No. (C):
The cube of minus x equals the opposite of the cube of x? That sounds plausible. In fact, (C)
is true. It doesn’t matter whether you take the opposite of a number first and then cube it, or
cube the number first and then take its opposite—you’ll get the same result both ways.39 . B
The first step in finding a limit is generally to factor: