Answer: C(x) = 0.25x + 75
Explanation:
C(x) appears to be a linear function in the form
y = mx + b, where m is the rate of change and b is the initial value
In this problem, the initial charge is 75, so b = 75.
It costs 0.25 per copy, so the rate of change is 0.25.
substitute as appropriate:
C(x) = 0.25x + 75