This math topic focuses on determining the domain of rational functions, where the denominator includes a linear expression. The students are provided with functions of the form \( f(x) = \frac{a}{bx+c} \), and they must identify the valid values of \( x \) that do not make the denominator zero, thereby avoiding undefined expressions. Each question presents a function with different coefficients in the linear denominator, and multiple-choice answers detail various potential domains using set notation and inequality symbols, testing the student's understanding of restrictions in rational functions.