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.
A. C(x) = 2x3 + 2x2 − 18x − 11
B. C(x) = 3x3 + 2x2 − 18x + 11
C. C(x) = 3x3 + 2x2 − 18x − 11
D. C(x) = 2x3 + 2x2 − 18x + 11

A

Step-by-step explanation:

To find our final equation, we need to subtract the decrease equation by the initial equation:

Here are the subtraction terms to find your C(x) function

Giving you the final answer of:

hiking down a winding trail.

step-by-step explanation:

c. y = 1/4 x + 5

step-by-step explanation:

first, put the equation of the line on the graph into slope-intercept form

(y = mx + b):   y = -4x + 8

second, a perpendicular line has to have "an opposite/reciprocal slope" to the original slope. so, find the "m" value in your original equation (it's -4, right? )

original slope: m = -4   perpendicular slope: change the sign to its opposite and find the reciprocal ("flip" the number)

new slope is now positive (b/c the original slope was negative 4), and it's 1/4 (not the original slope of 4 or 4/1)