It takes 4.3 seconds for the rocket to return to earth.
The equation is:

where -9.8m/sec² is the acceleration due to gravity, v₀ is the initial velocity, and h₀ is the initial height. We will go from the assumption that the rocket is launched from the ground, so h₀=0, and we are told that the initial velocity, v₀, is 42. This gives us:

We will use the quadratic formula to solve this. The quadratic formula is:

Plugging in our information we have:

x=0 is when the rocket is launched; x=4.3 is when the rocket lands.
f(18) = 39.50
This gives the monthly cost Kelsey will pay if she streams 18 movies in a month
Step-by-step explanation:
Given function is:

Here x is the number of movies
so for f(18), this means that the total number of movies will be 18
Solving

Hence,
f(18) = 39.50
This gives the monthly cost Kelsey will pay if she streams 18 movies in a month
Keywords: functions, Domain,range
Learn more about functions at:
#LearnwithBrainly
9.16515138991 es la raíz cuadrada
I believe the answer is cubic centimeter