reaction A+BAB. Suppose that the rate of the reaction is k, as in the example, but that the starting concentrations of the two reactants are [A]=3,[B]=1. (a) Explain why the rate of the reaction is then R(x)=k(3 x)(1x), where x is the concentration of the product AB. (b) What is the domain for R(x) ? And what is its range? (c) Suppose instead that the starting concentrations of A and B were [A]=6,[B]=3. Write the reaction rate R(x) as a function of the concentration, x, of AB. Find the domain and range of R(x)