SOLUTION: The height(in feet) of a firework t seconds after it is launched is given by H(t) = 3+180t-16t^ A. the firework is to explode at a height of at least 450 ft. B. Draw a graph of t

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: The height(in feet) of a firework t seconds after it is launched is given by H(t) = 3+180t-16t^ A. the firework is to explode at a height of at least 450 ft. B. Draw a graph of t      Log On


   

Question 479900: The height(in feet) of a firework t seconds after it is launched is given by H(t) = 3+180t-16t^
A. the firework is to explode at a height of at least 450 ft.
B. Draw a graph of the height of the firework over time, indicating the times when the firwork is at a height of at least 450 feet.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The height(in feet) of a firework t seconds after it is launched is given by H(t) = 3+180t-16t^
A. the firework is to explode at a height of at least 450 ft.
B. Draw a graph of the height of the firework over time, indicating the times when the firework is at a height of at least 450 feet.
:
Find the times when the device is at 450 ft
-16t^2 + 180t + 3 = 450
-16t^2 + 180t + 3 -450 = 0
-16t^2 + 180t - 447 = 0
Use the quadratic formula to find t; a=-16, b=180. c=-447
You should find the device will be at 450 ft: t ~ 3.7 sec and 7.55 sec
:
The graph of the equation -16t^2 + 180t + 3; where y axis is the height
+graph%28+300%2C+200%2C+-6%2C+20%2C+-200%2C+600%2C+-16x%5E2%2B180x%2B3%2C+450%29+
the green line is at 450 ft