Final answer:
The cost of one bush is derived by subtracting the total cost of the trees (7Y) from the total amount paid (X), which is represented as $X - 7Y for all four bushes.
Step-by-step explanation:
The cost of 4 bushes and 7 trees is given as a total of $X. If the cost of one tree is $Y, then the cost of 7 trees is 7Y. To find the cost of a bush, we need to subtract the total cost of the trees from the total cost $X. This leaves us with the cost for 4 bushes.
So the cost of 4 bushes is $X - 7Y. To find the cost of a single bush, we divide this total cost by 4. The formula to represent this is as follows:
Cost of one bush = ($X - 7Y) / 4
However, the answer choices do not provide an option that represents the cost divided by 4. Therefore, the closest correct option that represents the total cost of the bushes is c) $X - 7Y, which provides the total cost for all 4 bushes without the division.