You should have successfully completed courses in which you studied algebra, geometry, trigonometry, analytic geometry, and elementary functions. In particular, you should understand the properties of linear, polynomial, rational, exponential, logarithmic, trigonometric, inverse trigonometric, and piecewise-defined functions and know how to graph these functions and solve equations involving them.
You should also be familiar with algebraic transformations, combinations, compositions, and inverses for general functions.
I recommend watch this video before we start the semester. Neil deGrasse Tyson is an American astrophysicist, author, and science communicator.