Set up an equation that describes the relationship between the two variables sin each of the following.
Graph precisely that relationship.
Solve the system of two linear equations by algebraic elimination.
1. A restaurant is offering two special meals. The difference between seven times the orders for the first special and four times the orders for the second special is 12. The sum of three-fourths of the orders for the first special and two-thirds of the orders for the second special is 21. Find the number of orders for each special.
2. A machine requires four hours to make a unit of Product A and three hours to make a unit of Product B. Last month the machine operated for 200 hours producing a total of 60 units. How many units of each type of product did it produce?
3. A total of $18,000 is invested in two funds paying 8% and 9% simple interest. If the yearly interest is $1,510, how much of the $18,000 is invested at each rate?