Any help pls I need to pass

What is the value of x in the diagram below?

Giuseppi's pizza had orders for $931.00 of pizzas. the prices were $21 for a large pizza, 514 for a medium pizza, and $7 for a small pizza. the number of large pizzas was two less than four times the number of medium pizzas. thenumber of small pizzas was three more than three times the number of medium pizzas. how many of each size of pizza were ordered?

Aboat costs 19200 and decreases in value by 12% per year. how much will it cost in 5 years