<span>x cubed +3x squared - 4x= 0
= x^3 + 3x^2 -4x = 0
=x(x^2 +3x -4) = 0
= x (x+4)(x-1) = 0
x = 0
x+ 4 = 0 then x = -4
x - 1 = 0 then x = 1
answer: x = 0, x = -4 and x = 1</span>
Answer: The total amount the water change was -28 gallons by the end of the week <u>OR</u> The total amount the water changed decreased 28 gallons by the end of the week. Depending on how you want to word it.
Hope this helps!
Step-by-step explanation:
<u>Create you equation:</u>
x = the total amount the water changed
d = the amount of days
x = -4d
<u />
<u>Insert the known information into the equation and solve:</u>
x = -4d
x = -4(7)
x = -28
342
Explanation (18*8)+(9*10)+(18*6)