#15 please !! it would be a lot of help

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?

Find two numbers if their sum is 91 and the ratio is 6: 7?

Using inductive reasoning, what is the next two numbers in this set? 1,-7,13,-19 i got the numbers 14,-26 is that right?