Demand and supply curves are represented with the following equations.

Q_D = 600 - 3P Q_S = 7P - 300

Use the following given information toanswer questions 7 - 9.

Question 7

Explain why Q_D= 600 - 3P represents a demand equation.

Group of answer choices

The relationship between Q and P is negative.

The relationship between Q and P is positive.

It is because the equilibrium price is greater than the equilibrium quantity.

It is because the supply cannot be represented by an equation.

Question 8

When P = $80, find the quantity supplied.

Question 9

Find the equilibrium price.

Answer: The equilibrium price = $____________

Refer to the following graphs, which shows the market for good C. The current supply curve is S1.

Use the given information to answer questions 10 - 11.