Answer:
I think that I am right. One train is traveling at 75 mph and the other train is traveling at 91 mph
Step-by-step explanation:
For this case we have the following function:
<span>w (x) = - 5 (x-8) (x + 4)
</span><span>Rewriting we have:
</span><span>w (x) = - 5 (x ^ 2 + 4x - 8x - 32)
</span><span>w (x) = - 5x ^ 2 - 20x + 40x + 160
</span><span>w (x) = - 5x ^ 2 + 20x + 160
</span><span>Then, deriving we have:
</span><span>w '(x) = - 10x + 20
</span><span>We equal zero and clear x:
</span><span>0 = -10x + 20
</span><span>10x = 20
</span><span>x = 20/10
</span><span>x = 2 seconds
</span><span>Substituting values:
</span><span>w (2) = - 5 (2-8) (2 + 4)
</span><span>w (2) = - 5 (-6) (6)
</span><span>w (2) = 180 meters
</span>Answer:
The maximum height that the stone will reach is:
w (2) = 180 meters
