The Demand function of good z is

Q_Z= 100 - 2.5P_z - 0.65P_w + 3.0P_X + 0.8y

Where; Q_Z= quantity of good z

P_z = price of good z

y = income

P_w = price of good w

P_x= price of good x

Also given; P_X = $175; P_z = $100; P_w = $300 and y = $1000

Compute;

1. Cross price elasticity of Demand and Interpret your answer
2. How are goods w and x related to good z ?
3. Compute income elasticity of Demand and Interpret your answer
4. Is good z a luxury good or a necessity good? Explain