Answer:
The rule is y = 8 - x
Explanation:
* Lets explain how to solve the problem
- There are 8 oranges in a bowl
- The variable y represents the number of oranges that are left 
 in the bowl
- The variable x represents the number of oranges that are taken
 from the bowl
- To make the rule for these situation we must to write two sides equal
 each other
∵ The total number of oranges is 8
∵ The number of oranges that are taken from the bowl is x
∵ The number of oranges that are left in the bowl is y
- We can find the number of oranges that are left by subtracting the 
 number of oranges that are taken from the total number of oranges
∴ y = 8 - x ⇒ OR ⇒ y = -x + 8
* The rule for the number y of oranges that are left in the bowl as a
 function of the number x of oranges that are taken from the bowl
 is y = 8 - x