A physiotherapist purchased 7 rolls of resistance bands and 11 therapy balls for a total cost of $277. A second purchase, at the same prices, included 9 rolls of resistance bands and 14 therapy balls. The cost of the second purchase was $353. Find the unit cost for a resistance band and the unit cost for a therapy ball. Use a for unit cost of resistance bands and y for unit cost of therapy ball. a) Write the equation representing the total payment of the first purchase. b) Write the equation representing the total payment of the second purchase. Now solve for the answers c) Unit cost for resistance band: $ d) Unit cost for therapy ball: $