Question 1016037
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Set h=0. The rocket will be at 0 height twice:
once when launched (t=0) and again when it lands.
You want the difference between these two.
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{{{-16t^2+64t=0}}}
{{{t(-16t+64)=0}}}
{{{t=0}}} {{{OR}}} {{{-16t+64=0}}}
{{{t=0}}} {{{OR}}} {{{-16t=-64}}}
{{{t=0}}} {{{OR}}} {{{t=4}}}
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The rocket is launched at 0 seconds and lands at 4 seconds.
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ANSWER: The rocket is in the air for 4 seconds.
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