Question

(15 PTS) The function f(x) = –x^2 + 20x – 75 models the profit from one customer, in dollars, a shop makes for printing photos, where x is the number of photos printed, and f(x) is the amount of profit.

Part A: Determine the vertex. What does this calculation mean in the context of the problem?

Part B: Determine the x-intercepts. What do these values mean in the context of the problem?

Answer 1

f(x) = -x^2 + 20x - 75
fx/x + -x^2 + 20x -75/x
f = - x^2 = 20x + 75/x
f = - (x - 15)(x -5)/x