The demand curve is given by:

QD= 600-5PX-0.8 I + 15Py- 2Pz

a. Based on the demand curve above, is X a normal or an inferior good?

b. Based on the demand curve above, what is the relationship between good X and good Y?

c. Based on the demand curve above, what is the relationship between good X and good Z?

d. What is the equation of the demand curve if consumer incomes are $30,000, the price of good Y is $15,; graph and the price of good Z is $10?

e. Graph the demand curve in (d), showing intercepts and slope. Suppose the price of good Y rises to $20, Graph the new demand curve.