Tutors have the ability to create educational resources and share them with the WyzAnt community.
Here are some of the resources created by Amy.
View all of Amy’s resources

Yes, the compound interest formula is a function of time and principle invested. As to the other questions, they seem to refer to a discussion your book or class are having about types of functions, and I am not sure just what is wanted here. Exceptions
are the last two questions,...

Usually there are the same number of equations as there are unknowns, Savannah, unless the problem asks you to solve for one of the unknowns with respect to the other. For instance, in the problem you listed, you have the value of y with respect to x;
perhaps they want you to solve for...