Given the equations for demand and supply: Qd = 48 ? 4P and Qs = 4P ? 16, respectively, the market is in equilibrium when the quantity bought and sold is:

Blank DVDs and prerecorded DVDs are substitutes in production. An increase in the price of a blank DVD will lead to

A) an increase in the supply of prerecorded DVDs. B) a decrease in the supply of prerecorded DVDs. C) an increase in the quantity supplied of prerecorded DVDs but not in the supply of prerecorded DVDs. D) a decrease in the quantity supplied of prerecorded DVDs but not in the supply of prerecorded DVDs.

The value of the y-coordinate of a point in a graph is the length of a line from the point to the

A) origin. B) scalar. C) x-axis. D) y-axis.