The demand for good X is estimated to be Qxd = 10,000 - 4Px+ 5Py+ 2M + Ax, where Px is the price of X, Py is the price of good Y, M is income, and Ax is the amount of advertising on X. Suppose the present price of good X is $50, Py is $100, M is $ 25,000, and Ax =1,000 units. What is the demand curve for good X?