document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1138655>Question 1138655</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Jack hit a golf ball from the ground and its movement follows the equation h(t)=-16t^2+84t, where t is the time in seconds, and h(t) is the height of the ball at a given time t.\r<BR>\n" );
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document.write( "Find the time that it took the golf ball to hit the ground again correct to two decimal places.\r<BR>\n" );
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document.write( "                 seconds\r<BR>\n" );
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document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #756461 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=756461\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> set the equation -16t^2+84t=0, since the ground is presumably at h(t)=0<BR>\n" );
document.write( "-4t(4t-21)=0<BR>\n" );
document.write( "t=0 (at the start)<BR>\n" );
document.write( "t=21/4=5.25 seconds.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=graph%28300%2C300%2C-10%2C10%2C-10%2C120%2C-16x%5E2%2B84x%29 ALIGN=MIDDLE  ALT=\"graph%28300%2C300%2C-10%2C10%2C-10%2C120%2C-16x%5E2%2B84x%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
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