pLLLLSSSS HELPP IM MARKING BRAINLIEST
The water usage at a car wash is modeled by the equation W(x) = 3x3 + 4x2 − 18x + 4, where W is the amount of water in cubic feet and x is the number of hours the car wash is open. The owners of the car wash want to cut back their water usage during a drought and decide to close the car wash early two days a week. The amount of decrease in water used is modeled by D(x) = x3 + 2x2 + 15, where D is the amount of water in cubic feet and x is time in hours.

Write a function, C(x), to model the water used by the car wash on a shorter day.
C(x) = 2x3 + 2x2 − 18x − 11
C(x) = 3x3 + 2x2 − 18x + 11
C(x) = 3x3 + 2x2 − 18x − 11
C(x) = 2x3 + 2x2 − 18x + 11

W(x) is giving you the normal usage, D(x) is telling you by how much W(x) decreases. To find out what the actual usage is after the decrease we are going to have to subtract D(x) from W(x). I’m going to attach an image of how I did that, but basically your just subtracts the coefficients (number in front) where the exponents are the same. Also, don’t forget that since there is no x in D(x) we add in a +0X as a place holder.
I ended up with C(x)=2X^3+2X^2-18X-11 (option 1) Let me know if you have any questions.