How many black keys will appear on a pipe organ with a total of 240 keys?

What is the logarithmic function modeled by the following table? x f(x) 9 2 27 3 81 4

Which of the following are accepted without proof in a logical system? check all that apply.

In the polynomial below, what number should replace the question mark to produce a difference of squares? x2 + ? x - 36