5) i need help asa True/False In the he expression ( x^2 * y) / z , z varies jointly with the product of the square of x and y

Rita wants to buy sweater that was originally priced at $25 today the sweater is on sale for 40% off the original price what is the sale price of the sweater. rita has a coupon for an addition 10% off the sale price. how much will rita pay for the sweater before taxes

If x = 12 and y = 3, what is the value of x - y 2? 81 6 3 18

How do i do this activity, is appreciated