Jamie bought a total of 20 pounds of grass seed at the nursery for $168. He paid $9 per pound for Kentucky bluegrass and $6 per pound for Tall Fescue. Which system of equations can be used to find the amount x (in pounds) of Kentucky bluegrass and the amount y (in pounds) of Tall Fescue Jamie purchased? Determine the number of pounds of Kentucky bluegrass and the number of pounds of Tall Fescue that Jamie purchased from the problem above.