There are several ways to combine two functions, such as addition, subtraction, multiplication, and division of the functions. Another way is function composition, where one function is applied to the output of another function. With composition, the functions are applied from the inside out - first evaluate the inner function, then apply the outer function to the result. Examples show how to evaluate various compositions of the functions f(x) = 2x + 1 and g(x) = x^2.