Please help with all parts

1. (7 points) Dave Grohl wants to buy drums and guitars. Drums are sold in an unusual way. There is only one supplier, and the more drums you buy from him, the higher the price you have to pay per unit. In fact, y units of drums will cost Dave y dollars. Guitars are sold in the usual way at a price of 2 dollars per unit. Dave's income is 20 dollars and his utility function is U(x, y) = a + 2y, where x is his consumption of guitars and y is his consumption of drums. A. Sketch Dave's budget set and shade it in. B. Sketch some of his indifference curves and label the point that he chooses. C. Calculate the number of drums and guitars that Dave demands at these prices and this income