9. At the Holiday Valley Ski Resort, skis cost to rent and snowboards cost . If 28 people
   rented on a certain day and the resort brought in , how many skis and snowboards were
   rented?

To solve this, let’s define two variables: let be the number of skis rented and be the number of snowboards rented. We can set up the following system of equations based on the information given:

Now, using the first equation, express in terms of :

Substitute this into the second equation:

Now, simplify and solve for :

Combine like terms:

Subtract 532 from both sides:

Now, divide by -3:

Now, substitute back into the first equation to find :

Thus, 18 skis and 10 snowboards were rented.

To summarize, the solution is:
18 skis and 10 snowboards were rented.