Consider that the demand for a certain brand of women’s shoes is given by, and the supply of these shoes is given by, where p is the price in dollars and q is the number of pairs at price p.

Let us solve the system containing these two equations to find the equilibrium price and the equilibrium quantity.

To do this, we can solve this system by elimination method.

...... (1) Rearrange the terms in.

...... (2)

Multiply both sides of (2) by.

...... (1)

...... (2)

Now add these two equations.

Divide both sides by 7.