The system of equations that could be used to determine how many of each item were sold is:
C.
x + y + z = 87
y = z + 5
4.5x + 6y + 7.5z = 489
A system of equations is when two or more variables are related, and equations are built to find the values of each variable.
For this problem, the variables are given as follows:
87 items in total were sold, hence:
x + y + z = 87.
The total earned was of $489, hence:
4.5x + 6y + 7.5z = 489.
The vendor sold 5 more items for $6.00 than for $7.50, hence:
y = z + 5.
These three equations are given in option C.
More can be learned about a system of equations at https://brainly.com/question/24342899
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