Quadratic equation

Question

A rocket is launched from a tower. The height of the rocket, y in feet, is related to the time after launch, x in seconds, by the given equation. Using this equation, find the time that the rocket will hit the ground, to the nearest 100th of second.

y

=

−

16

x

2

+

251

x

+

105

y=-16x^2+251x+105

y=−16x

2

+251x+105

Answer 1

when the rocket hits the ground, y = 0

0 = -16x^2+251x+105

x = -.4077 (ignore this answer as negative time makes no sense)

x = 16.0952 sec

I used the quadratic on my calculator.