Sample Problem

The demand and supply equations for a new gadget that can calculate your mood at any given point in time are given by

where p is the price in dollars and x represents the number of units. Find the equilibrium point for this market.

Equilibrium point:

x= gadgets (round to nearest whole unit)

p= $ (round to the nearest whole dollar)


The equilibrium point is the price p and number of units x that satisfy both the demand and supply equations.

Substitute the value of p given in the supply equation into the demand equation (p is written already conveniently in terms of x)




So, the equilibrium point occurs when the demand and supply are each 24,000 units. The price that corresponds to this x-value can be obtained by back-substituting x=24,000 back into either of the original equations.