Hello I need help solving these. Question is attached

Understanding Demand Curves 1. Suppose quantity demanded for good z is given by QDz = 500 - 50Pz + 10Y - 42Px , where x and z are two different goods and Y represents income. a. Is good x a normal or inferior good? b. Is good z a normal or inferior good? c. Are goods x and z complements or substitutes? d. Now suppose quantity supplied for good z is given by QSz= 50Pz - 400. Let's also assume Px = $1 and Y = 10. Find equilibrium price and quantity. e. Is the market equilibrium efficient? How do you know