OG详解-OG2 数学1 Q5

Choice C is correct. It’s given that  f(x) is the total cost, in dollars, to lease acar from this dealership with a monthly payment of x dollars. Therefore, the total cost, in dollars, to lease the car when the monthly payment is  $400  is represented by the value of f(x) when x = 400. Substituting 400  for x in the equation f(x)= 36x +1,000 yields f(400)= 36 (400)+1,000, or f(400)= 15,400 . Thus,when the monthly payment is  $400, the total cost to lease a car is  $15,400 .
Choice A is incorrect and may result from conceptual or calculation errors. Choice B is incorrect and may result from conceptual or calculation errors. Choice D is incorrect and may result from conceptual or calculation errors.