Select the correct answer from each drop-down menu. a function is a relation where each input value is assigned to exactly, less than, or at least one output value. the domain, rate of change, interval, or range of a function is the set of all input values, or x-values, for which the function is defined. the interval, domain, rate of change, or range of a function is the set of all output values, or y-values, for which the function is defined. to write the equation y = ax + b in function notation, x, b, f(x), or a substitute for y.