I have doubts on the result I get on this answers

1.We have the following sales function: Qx= -4Px+2Py+0.2I+0.04APx= $200, the Price of good X, Py=$140, the price of good Y, I=2,000, income, A=$15,000 advertising expenditures. Given the above information the derived demand function is equal to: Simplified function

2.Suppose that the market of cellular phones, an inferior good, is an equilibrium. Then a decrease in consumers' income due to a recession, everything else constant, will...

3.The price elasticity of demand for the Ipod is equal to -1.5. Assuming all other variables equal, a 10% decrease in price of Ipod would:

Thank you,