Economics Homework Help: Supply, Demand, Elasticity & Equilibrium

Write down the product or service, the market being analysed and the change described in the question. Separate a change in the product's own price from changes in income, tastes, input costs, technology, taxes or the number of buyers and sellers.

For a graph, label the vertical axis as price and the horizontal axis as quantity, then draw demand and supply. Clearly mark the initial equilibrium before showing the effect of the change.

A change in the good's own price generally produces a movement along a given demand curve, all else equal. A change in a demand determinant, such as consumer income for a normal good, can shift the demand curve. Similarly, input-cost changes can shift supply.

For example, if the price of coffee rises while other factors remain fixed, the quantity demanded may decrease along the demand curve. If coffee becomes more popular at every price, demand shifts to the right. State the cause before describing the graph.

Equilibrium occurs where quantity demanded equals quantity supplied. If the problem provides equations, set them equal and solve for the equilibrium price, then substitute that price into either equation to find quantity.

Check that the quantity demanded and supplied match at your result. If you solve only for price or draw a graph without explaining the intersection, you may not have answered every part of the question.

Price elasticity of demand measures the responsiveness of quantity demanded to a price change. In many introductory problems, elasticity is calculated as the percentage change in quantity demanded divided by the percentage change in price. The midpoint method is often useful when comparing two points because it uses the average of the starting and ending values as the base.

Elasticity is commonly negative under the usual demand relationship, but assignments sometimes discuss the absolute value. Follow the convention specified in the question and explain whether demand is elastic, inelastic or unit elastic based on that convention.

A good response explains why the curve shifts or why a movement occurs, then states the expected direction of equilibrium price and quantity. If the question asks for evaluation, note assumptions or factors that could change the result, such as time horizon or availability of substitutes.

Avoid treating a graph as proof by itself. Your text should connect the scenario to the curve and explain how the conclusion follows from the economic model.