Suppose, we have the following demand and supply relationships:
        Demand: Q_D = 40 - P
        Supply: Q_S = -60 + 3P

We learned that we can find the equilibrium price and quantity by equating them and solving for the price:
        40 - P = -60 + 3P
        100 = 4P
        P = 25
        Q = 15

Now, suppose supply shifts out so that the new supply relationship is:
        Q_S2 = -40 - 3P .

We can now solve for the new equilibrium:
        40 - P = -40 + 3P
        80 = 4P
        P = 20
        Q = 20

Once again, our simple mathematical model confirms the result of our graphical market analysis: When supply shifts out, equilibrium price falls and quantity rises.