please answer. No additional info given to this question. Part a does not relate to part b

(b) 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 Pi and ym = 0.57 PE, 1 y where Px and P3, are the prices of goods at and 3/ respectively and M is her income. Determine whether this set of demand functions is valid