please make the answers very clear. Thank you

Example 2// Every time a function is composed with itself, it is called an iteration. Iterations can be noted using a superscript. For this example, use the function f(x) = =x + 1 and an initial value of 4. Note that Function compositions can create iterations as well. with each successive iteration, you can use the previous output as your new input to the function. . 5( 4 ) = - 4+1 0