document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1093126>Question 1093126</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A rock is tossed straight up with initial velocity of 10 feet per second from atop a balcony 30 ft above the ground. The height of the rock is given by the equation h(t) = -16t^2 + 10t + 30 at a time t seconds after the rock was tossed. How many seconds pass before the rock is 20 feet above ground? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #707722 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=707722\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Since the rock is tossed from a height above<BR>\n" );
document.write( "20 ft, then the rock will be falling at 20 ft<BR>\n" );
document.write( "-----------------------------------------<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+h%28t%29+=+-16t%5E2+%2B+10t+%2B+30+ ALIGN=MIDDLE  ALT=\"+h%28t%29+=+-16t%5E2+%2B+10t+%2B+30+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+20+=+-16t%5E2+%2B+10t+%2B+30+ ALIGN=MIDDLE  ALT=\"+20+=+-16t%5E2+%2B+10t+%2B+30+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+-16t%5E2+%2B+10t+%2B+10+=+0+ ALIGN=MIDDLE  ALT=\"+-16t%5E2+%2B+10t+%2B+10+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+-8t%5E2+%2B+5t+%2B+5+=+0+ ALIGN=MIDDLE  ALT=\"+-8t%5E2+%2B+5t+%2B+5+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Use quadratic formula<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+=+-8+ ALIGN=MIDDLE  ALT=\"+a+=+-8+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+5+ ALIGN=MIDDLE  ALT=\"+b+=+5+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+5+ ALIGN=MIDDLE  ALT=\"+c+=+5+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28-5+%2B-+sqrt%28+5%5E2-4%2A%28-8%29%2A5+%29%29%2F%282%2A%28-8%29%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28-5+%2B-+sqrt%28+5%5E2-4%2A%28-8%29%2A5+%29%29%2F%282%2A%28-8%29%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28-5+-+sqrt%28+25+-%28+-160+%29+%29+%29+%2F+%28-16%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28-5+-+sqrt%28+25+-%28+-160+%29+%29+%29+%2F+%28-16%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28+-5+-+sqrt%28+185+%29+%29+%2F+%28-16%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-5+-+sqrt%28+185+%29+%29+%2F+%28-16%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28+-5+-+13.601+%29+%2F+%28-16%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-5+-+13.601+%29+%2F+%28-16%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+18.601%2F16+ ALIGN=MIDDLE  ALT=\"+t+=+18.601%2F16+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+1.163+ ALIGN=MIDDLE  ALT=\"+t+=+1.163+\"   DISABLED_style= \"max-width:90%; height:auto;\" > sec<BR>\n" );
document.write( "---------------------<BR>\n" );
document.write( "check answer:<BR>\n" );
document.write( "here's the plot:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+graph%28+400%2C400%2C+-1%2C3%2C+-5%2C40%2C+-16x%5E2+%2B+10x+%2B+30+%29+ ALIGN=MIDDLE  ALT=\"+graph%28+400%2C400%2C+-1%2C3%2C+-5%2C40%2C+-16x%5E2+%2B+10x+%2B+30+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Looks about right\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );