Final answer:
The question seems to revolve around finding a pattern or sequence that results in a simplified form of 2n², but without the complete sequence of functions or contexts, it is not possible to provide the exact expression for yn(x).
Step-by-step explanation:
To find the general simplified form of the function yn(x) in terms of n, given that the starting function is f(x)=2x-1, we need to understand the recursive nature of the sequences or functions provided. It seems from the context clues and the incomplete prompt provided that we are dealing with some series or numerical pattern that relates to the function in question. Based on the pattern that "the expression in the box is = n²" and the following operations, it suggests that we are looking at some sequence of operations that can be simplified to a general form of 2n². However, without the actual sequence of functions or additional context, deriving the exact expression for yn(x) is not possible. Thus, a clear and concise step-by-step explanation cannot be given due to the lack of complete information from the question.