check the picture below.
so, the rocket will come back to the ground when h(t) = 0, thus
![\bf h(t)=-3t^2+12t\implies \stackrel{h(t)}{0}=-3t^2+12t\implies 0=-3t(t-4)\\\\[-0.35em]~\dotfill\\\\0=-3t\implies 0=t\impliedby \textit{0 seconds when it took off from the ground}\\\\[-0.35em]~\dotfill\\\\0=t-4\implies 4=t\impliedby \textit{4 seconds later, it came back down}](https://tex.z-dn.net/?f=%5Cbf%20h%28t%29%3D-3t%5E2%2B12t%5Cimplies%20%5Cstackrel%7Bh%28t%29%7D%7B0%7D%3D-3t%5E2%2B12t%5Cimplies%200%3D-3t%28t-4%29%5C%5C%5C%5C%5B-0.35em%5D~%5Cdotfill%5C%5C%5C%5C0%3D-3t%5Cimplies%200%3Dt%5Cimpliedby%20%5Ctextit%7B0%20seconds%20when%20it%20took%20off%20from%20the%20ground%7D%5C%5C%5C%5C%5B-0.35em%5D~%5Cdotfill%5C%5C%5C%5C0%3Dt-4%5Cimplies%204%3Dt%5Cimpliedby%20%5Ctextit%7B4%20seconds%20later%2C%20it%20came%20back%20down%7D)
Use the foil method
FIRST
OUTER
INNER
LAST
9x by 5x
9x by -7
-12 by 5x
-7 by -12
Then add and subtract like terms to get the answer.
Answer:
24 1/2
Step-by-step explanation:
Answer:
558.036 lb
Step-by-step explanation:
Let x is the amount of the sea water to collect 125 lb of sea salt
As given: 64 lb/ft³ has 0.0035 dissolved salt by weight
So the formula to find out the amount of the sea water is:
64 lb/ft³ * 0.0035 *x ft³ = 125 lb
<=> x =
= 558.036 lb
Hope it will find you well.