Really need help with this math question! Thanks!

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

Question

Really need help with this math question! Thanks!

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

Axolotl · Answer

REALLY NEED HELP ON THIS

Mooshroom · Answer

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

Mooshroom · Answer

@mooshroom wrote:

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

Hope it helps! ♡