please answer 2ab

g. [20 marks] (a) Consider the expenditure function E *(Px, P3,, 3) = PxD'SPyO'TU, where > 0. Determine whether this function is a valid expenditure function. 03) Consider an individual who consumes only two goods, 96 and 3!. She cannot borrow money and does not save money. Her Marshallian demand functions are xm = 0.8 P3 and ym = 0.57 p' x 3" where Px and P3, are the prices of goods 36 and y respectively and M is her income. Determine whether this set of demand functions is valid