Final answer:
Equilibrium in the goods market can be described using the supply and demand framework where quantity demanded equals quantity supplied, or via the income-expenditure model where aggregate expenditure equals total output.
Step-by-step explanation:
Two equivalent ways of describing equilibrium in the goods market are through the supply and demand framework and the income-expenditure model. Firstly, equilibrium in the goods market can be seen where the quantity demanded equals the quantity supplied, implying that the market price is such that consumers are willing to buy exactly as much as producers are willing to sell.
Secondly, in the income-expenditure model, the goods market is in equilibrium when aggregate expenditure, which consists of consumer spending, investment, government spending, and net exports, equals total output or income. At this point, there is no incentive to increase or decrease production because the amount being produced is being purchased entirely, meaning aggregate demand equals aggregate supply.