In a bimolecular reaction A + B → M, a moles per liter of a substance A and b moles per liter of a substance B are combined. Under constant temperature the rate of reaction is y' = k(a – y) (b – y) that is, y' is proportional to the product of the concentrations of the substances that are reacting, where y(t) is the number of moles per liter which have reacted after time t Solve this ODE, assuming that a ≠ b.