SOLUTION: I just can't get the following problem from my Algebra book: A rocket is launched from atop a 77-foot cliff with an initial velocity of 82 feet per second. The height of the rocke

Question 38358: I just can't get the following problem from my Algebra book:
A rocket is launched from atop a 77-foot cliff with an initial velocity of 82 feet per second. The height of the rocket t seconds after launch is given by the equation h=-16t^2+82t+77. Graph the equation to find out how long after the rocket is launched it will hit the ground. Estimate your answer to the nearest tenth of a second.

Answer by Nate(3500) (Show Source): You can put this solution on YOUR website!

Use quadratic formula to determine the zeros.

Solved by pluggable solver: SOLVE quadratic equation with variable

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=11652 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: -0.810763442128409, 5.93576344212841. Here's your graph:

Since the time can not be negative, the answer is about 5.9 seconds.
RELATED QUESTIONS
A rocket is launched from atop a 101 - foot cliff with an initial velocity of 116... (answered by Alan3354)

Ok so the problem is A rocket is launched from atop a 41 foot cliff with an initial... (answered by rothauserc,Alan3354)

a rocket is launched from atop a 32-foot cliff with an initial velocity of 154 ft/s.... (answered by venugopalramana)

A rocket is launched from atop a 114-foot cliff with an initial velocity of 131 ft/s. Use (answered by ikleyn)

Everyone in my family has tried to answer this worksheet from school. Does it need to be (answered by Earlsdon,bucky)

A rocket is launched from atop a 101 foot cliff with an initial velocity of 116 feet per... (answered by Boreal)

A rocket is launched from atop a 92 foot cliff with an initial vertical velocity of 112... (answered by Earlsdon)

A rocket is launched from atop a 43-foot cliff with an initial velocity of 70 feet per... (answered by Alan3354)

A rocket is launched from atop a 54-foot cliff with an initial velocity of 119 feet per... (answered by josmiceli)