Final answer:
To solve the function (2x - S) for f(x) = 15, we solve for 2x = 15, which yields x = 7.5. However, this does not match any of the provided answer choices, hinting at a possible issue with the question or answer options.
Step-by-step explanation:
To find the value of x that makes f(x) = 15, given the function expression (2x - S), we need to solve the equation 2x - S = 15. Since 'S' is not standard mathematical notation and was mentioned to be ignored due to a typo, we proceed on the presumption that 'S' is meant to represent a constant value or is an irrelevant part of the question. Therefore, with 'S' omitted, the equation simplifies to 2x = 15. Dividing both sides by 2 gives us x = 7.5. However, this value does not match any of the provided multiple-choice options (A. 5, B. 10, C. 20, D. 25), so it appears there may have been a misunderstanding in the question itself or the provided options could be incorrect based on the given expression.