This math topic focuses on determining the domains of function compositions, specifically compositions of a rational function with a linear function. It assesses understanding of how to handle divisions by expressions and finding values that prevent the function from being undefined (like avoiding division by zero). The task involves evaluating function compositions like "f(g(x))" where "f" is predominantly of the form "k/x" and "g(x)" is a simple linear function. The goal is to identify from given options the correct domain of these composite functions, ensuring mathematical correctness in function operation and input restrictions.