In the exercise Number 5.7 about David quasilinear function, I know I have to use the budget constraint equation and the tangency equation, how do I derive the demand curve for x and y?

the con- Sumer's purchases of clothing. 5.10 Use the income consumption curve in Figure 5.2(a) to draw the Engel curve for clothing, assuming the price of food is f2 and the price of clothing is $4. (a) A normal good has a positive income elasticity of demand. (b) A good whose income elasticity of demand is positive will be a normal good. 6 Ann consumes five goods. The prices of all goods are fixed. 5.11 The price of good x is pr. She spends 25 percent of her income on good x, regardless of the size of her income. (a) Show that her income elasticity of demand of good x is the same for any level of income, and determine its value. 5.12 (b) Would the value of the income elasticity of demand for x be different if Ann always spends 60 percent of her income on good x? David has a quasilinear utility function of the form U(x, y) = Vx + y, with associated marginal utility func- tions MUx = 1/(2Vx ) and MUy = 1. (a) Derive David's demand curve for x as a function of the 5.13 prices, Px and Py. Verify that the demand for x is independ- ent of the level of income at an interior optimum. (b) Derive David's demand curve for y. Is y a normal good? What happens to the demand for y as P. increases? .8 Rick purchases two goods, food and clothing. He has a diminishing marginal rate of substitution of food for cloth- ing. Let x denote the amount of food consumed and y the amount of clothing, Suppose the price of food increases