Demand estimation: Qxd = 100 - 3Px + 4Py - 0.01M + 2Ax.
where Ax represents the amount of advertising spent on shoe (x), Px is the price of good X, Py is the price of good Y and M is average income. Suppose good X sells at RM25 a pair, good Y sells at RM35, the company utilizes 50 units of advertising, and average consumer income is RM20 000. find out and interpret the own price, cross price, and income elasticity of demand.