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.
All of the answers are correct except the last one
Answer:
5.5 7
Step-by-step explanation:
It might be hard at first to find the hundreds place. The answer is C:722,357,000