work due in 10 min

Question

You plan to buy x books for $4 each. The function f(x) = 4x represents the total cost of the books. You have a coupon for 10% off of the total price of the books. Let the function g(x) represent the cost of the books after the coupon. Write g(x) as a transformation of the function f(x), then simplify the equation. Choose the correct letter.

 

 

A. g(x) = (0.1)f(x) = (0.1)(4x) = 0.4x

 

B. g(x) = f(x) + 0.1f(x) = (1.1)f(x) = (1.1)(4x) = 4.4x

 

C. g(x) = f(x) − 0.1f(x) = (0.9)f(x) = (0.9)(4x) = 3.6x

 

D. g(x) = f(x) − 0.1 = 4x − 0.1

 

 

 

 

Answer 1

If f(x) = 4x = total price for the books, then to apply the 10% coupon means that we subtract 10% of the total cost of the books from f(x) to find the discounted price. In other words, 

 

4x - 0.1 (4x), which is the same as f(x) - 0.1 f(x) = 0.9 f(x) = 0.9 (4x) = 3.6x

 

The correct answer is C.