Answer: 245 feet
Step-by-step explanation:
Given: The height of the rocket after t seconds is represented by the formula:

[Differentiate both sides w.r.t. t]
Put

Also,
i.e. height is maximum at t=7.
Maximum height = 
Hence, the maximum height the rocket reaches = 245 feet.
To determine the slope, you can use the following formula:
(y2-y1)/(x2-x1)
Answer:
I think the answer is $3.50, but I am not sure. Just doing quick math over here :)