document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=969451>Question 969451</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A rocket is launched from a cliff and it can be represented by the following function. h(t)= -16t squared + 80t + 384, where x is the time in seconds and h is the height of the rocket. How long did it take the rocket to reach the maximum height? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #592339 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=592339\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If we graph f(t)=-16t^2 + 80t  + 384, we'd see a convex upward parabola. The ordinate scale is 75 feet per tick. The vertex has a t value (x-axis) equal to  -b/2a, where b  is the coefficient of the middle term, and a is the coefficient of the leading term. \r<BR>\n" );
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document.write( "Vertex t value is therefore (-80/-32)=+2.5 seconds=t\r<BR>\n" );
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document.write( "Height is (-16)(2.5^2) + 80(2.5) + 384\r<BR>\n" );
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document.write( "Height=-100 + 200 + 384= 484 feet.\r<BR>\n" );
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