Suppose That the Demand and Supply Functions for Good X $Q _ { d } = 75 - 3 P$

Suppose that the demand and supply functions for good X are $Q _ { d } = 75 - 3 P$ $Q _ { s } = - 20 + 6.5 P$
a. Equilibrium price is $__________ and equilibrium quantity is __________ units.
b. If price is $8, then a ______________ of _______ units occurs. If price is $12, then a _____________ of _________ units occurs.
c. Let the demand function change to
$Q _ { d } = 80 - 6 P$ . Given the ORIGINAL supply function, the equilibrium price is $__________ and equilibrium quantity is __________ units.
d. Let the supply function change to
$Q _ { s } = - 40 + 12 P$ . Given the ORIGINAL demand function, the equilibrium price is $__________ and equilibrium quantity is __________ units.