Confused finding time for h = 180 if h = -16t^2 + 112t

jdruopp

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Apr 27, 2007
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The equation h= -16t^2 +112t gives the height of an arrow shot upward from the ground with an initial velocity of 112 ft/s, where t is the time after the arrow leaves the ground. Find the time it takes for the arrow to reach a height of 180ft.

Do I plug 180 in for h?

180=-16t^2 +112t
0= -16t^2 +112t - 180

Then....quadratic equation?
 
Yep; first, simplify (divide by 4) and change signs:
4t^2 - 28t + 45 = 0
 
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