You just literally have to make the following substitutions, for instance, f(w) = 2w^3-5 implies that f(4) = 2(4)^3-5, expanding the corresponding operation yields the result. Therefore, where you see a "w" in the function, substitute for the indicated value. The same goes in the fourth question, just substitute the whole "inner" function into the variable of the "outter" function. For the Python excersices, you can "cheat" a little bit, program what is asked and see what happens. Pay special attention to how you're defining your functions and, if you will, change the codes a little bit to see what happens. Experimentation teaches very well. Greetings!