A waste management company offers containers that can hold 10, 15, or 20 cubic yards of material. The cost of renting a 10-cubic-yard container is x dollars per year, the cost of renting a 15-cubic-yard container is y dollars per year, and the cost of renting a 20-cubic-yard container is z dollars per year. Write an expression that a customer can use to calculate the total annual cost of renting two 10-cubic-yard containers, four 15-cubic-yard containers, and three 20-cubic-yard containers.