V6 motor Under the theoretical framework of the theory, the theory of commodity market equilibrium and the monetary market equilibrium of Keynesian theory are unified. Marx's theory of interest rate decisions from the perspective of the source and essence of interest, taking into account the institutional factors in the role of interest rate decisions of interest theory, its theoretical core is the interest rate is determined by the average profit margin. Marx believed that under capitalism, interest is a part of profit and a form of conversion of surplus value. The basic economic unit of society in the primitive society of the clan, tribe, slave owners in the slave society, feudal society's family and the manual workshop, after the evolution of the form of this modern form in a capitalist society was born enterprise. The current GB/T3730.1-2001 car is divided into passenger cars and commercial vehicles. On the basis of introducing marginal concepts and mathematical argumentation, neoclassical has established a formal "perfect" mathematical model for the neoclassical "laissez-faire order" : general equilibrium. The price is the most important independent variable in this model, which can also be called price mechanism. The process of achieving general equilibrium is also a process of social resources guiding the flow of prices, so the price mechanism regulates the allocation of social resources.