Answer:
Step-by-step explanation:
Let function p(x) be the price that is reduced by 15% if the bill is x dollars.
Since the price is not payed in full 100% is reduced by 15% we only pay
100 - 15 = 85 % of the original price.
p(x) = x· (100% - 15 %) = x· 85% = 0.85 x
The function used to calculate any bill that is reduced by 15% is:
p(x) = 0.85x
x - is the bill before being reduced by the coupon