The user-friendly version of this content is available here.

The following content is copyright (c) 2009-2013 by Goods of the Mind, LLC.

This problem trains for: AMC-10, SAT-II, AMC-12.

Which of the answer choices must be true if it is true that:

equation

Since:

equation

it follows that the function is actually the constant function:

equation

However, the other two conditions must be true in order for the logarithm to exist.