You can first multiply your coefficients (7x9), which gives you 63. You can then simplify the exponents by using the rule that when two terms with the same variable are being multiplied, you can simplify by adding exponents. Since 7+3= 10, your simplified answer would be 63x^10 :) hope it helped!
A would be the correct answer:)
Hope this helps!
The whole thing flips around and ends up being t = 3k/?
The height of the rocket is found in terms of the angle as
.. h/(3 mi) = tan(θ)
.. h = (3 mi)*tan(θ)
Then the rate of change of height (vertical velocity) is
.. h' = (3 mi)*sec(θ)^2*θ'
.. h' = (3 mi)*4*(1.5 rad/min)
.. h' = 18 mi/min
The rocket's velocity is 18 miles per minute at that moment.

If the number you are rounding is followed by 5, 6, 7, 8, or 9, round the number up (+1).