### Home > INT2 > Chapter 9 > Lesson 9.3.4 > Problem 9-121

9-121.

Chad is entering a rocket competition.

Chad programs his rocket to launch straight up into the air with the function

, whererepresents the height in feet, andrepresents the time in seconds. How long after the launch does the rocket reach the ground?When it hits the ground, what is the height?

Solve the quadratic.

When

,seconds.Write and solve an inequality that shows when (during what time period) the rocket is at least

feet high. seconds In order to qualify, the rocket must be at least

feet off the ground for four seconds. Does Chad’s rocket qualify? For how many seconds is the rocket above

feet. What is an appropriate domain for the function in this situation?

For what times is the height greater than or equal to zero?