Question

The water usage at a car wash is modeled by the equation W(x) = 5x3 + 9x2 − 14x + 9, 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.

Answer 1

Answer:

C(x) = 4x³ + 7x² − 14x - 6

Step-by-step explanation:

In a shorter day the water used by the car wash is computed as the difference between the original usage and the decrease, that is:

C(x) = W(x) - D(x)

Replacing with data:

C(x) = 5x³ + 9x² − 14x + 9 - (x³ + 2x² + 15)

C(x) = 5x³ + 9x² − 14x + 9 - x³ - 2x² - 15

C(x) = (5-1)x³ + (9-2)x² − 14x + (9-15)

C(x) = 4x³ + 7x² − 14x - 6

Answer 2

C(x) = 4x³+7x²-14x-6

Step-by-step explanation:

Given that the amount of water used in normal days is given by the equation;

W(x) = 5x³ +9x²-14x +9 -----(i)

The amount of decrease in water used is modeled by the equation;

D(x)= x³+2x² +15--------(ii)

To get the function C(x) that models the water used by the car wash on shorter day you subtract equation (ii) from equation(i)

 5x³ +9x²-14x +9

-  x³+2x² +15

-------------------------

4x³+7x²-14x-6

Learn More

Subtraction in polynomials : brainly.com/question/2273346

Keywords : equation, modeled,

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