document.write( "Question 203283: The equation h=-16t^2+47t+3 gives the height h, in feet, of a football as a function of time t, in seconds, after it is kicked. How long does it take for the football to hit the ground? \n" ); document.write( "

Algebra.Com's Answer #153377 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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The equation h=-16t^2+47t+3 gives the height h, in feet, of a football as a
\n" ); document.write( " function of time t, in seconds, after it is kicked.
\n" ); document.write( " How long does it take for the football to hit the ground?
\n" ); document.write( ":
\n" ); document.write( "When it hits the ground h=0, therfore:
\n" ); document.write( ":
\n" ); document.write( "-16t^2 + 47t + 3 = 0
\n" ); document.write( "Multiply by -1, easier to factor
\n" ); document.write( "16t^2 - 47t - 3 = 0
\n" ); document.write( "factors to
\n" ); document.write( "(16t + 1)(t - 3) = 0
\n" ); document.write( "Positive solution
\n" ); document.write( "t = 3 seconds for the football to hit the ground
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\n" ); document.write( "Check solution when t = 3:
\n" ); document.write( "h = -16(3^2) + 47(3) + 3
\n" ); document.write( "h = -16(9) + 141 + 3
\n" ); document.write( "h = -144 + 141 + 3
\n" ); document.write( "h = 0 \n" ); document.write( "

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