Question 1152212
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(a)


fixed costs = insurance and car payments (these do not change no matter how many miles you drive)
mileage costs = cost of gas, oil, & maintenence (these do change based on how many miles you drive)


x = number of miles
0.25x = cost of driving x miles = mileage costs
360 = monthly fixed cost
360*12 = 4320 = annual fixed cost


f(x) = annual cost of driving x miles
f(x) = (mileage costs) + (annual fixed costs)
f(x) = (0.25x) + (4320)
f(x) = 0.25x+4320


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(b)


The y intercept represents the starting cost, or initial cost. In other words, if you drive x = 0 miles, then the total cost would be $4,320. 


Of course you'll likely drive some number of miles, so you'll add on whatever the result of 0.25x would be.


The y intercept is where the graph crosses the y axis.
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