<span>-7 x (-9) = +63
because if we multiply negative by negative we obtain +</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
X=cubic root 2/27
Glad to help
