Final answer:
The coefficient 8 represents the cost per unit of the variable f in the total cost to install a design, increasing the total cost by 8 dollars for each unit of f.
Step-by-step explanation:
The coefficient 8 in the expression 0.5v + 8f + 12s represents the cost in dollars for each unit of the variable f when calculating the total cost to install your design. This means that for every unit increase in f, the total cost will increase by 8 dollars.