document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=882146>Question 882146</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me solve this word problem: A disc is thrown into the air and follows a path modeled by the function h(t)=7.8+22t-5t^2, where time, t, is in seconds and height h(t) is in meters. Determine when the ball will land to the nearest hundredth. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #532714 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=532714\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The equation is a parabola<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+h%28t%29+=+-5t%5E2+%2B+22t+%2B+7.8+ ALIGN=MIDDLE  ALT=\"+h%28t%29+=+-5t%5E2+%2B+22t+%2B+7.8+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The ball is released at <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+0+ ALIGN=MIDDLE  ALT=\"+t+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+h+=+7.8+ ALIGN=MIDDLE  ALT=\"+h+=+7.8+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "-----------------------------<BR>\n" );
document.write( "You want to know what <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+ ALIGN=MIDDLE  ALT=\"+t+\"   DISABLED_style= \"max-width:90%; height:auto;\" > is<BR>\n" );
document.write( "when <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+h+=+0+ ALIGN=MIDDLE  ALT=\"+h+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" > for the 2nd time<BR>\n" );
document.write( "( the ball comes back to earth )<BR>\n" );
document.write( "---------------------------<BR>\n" );
document.write( "This is the same as finding both of<BR>\n" );
document.write( "the roots of the equation<BR>\n" );
document.write( "Set <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+h%28t%29+=+0+ ALIGN=MIDDLE  ALT=\"+h%28t%29+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" > and use the<BR>\n" );
document.write( "quadratic formula to find roots<BR>\n" );
document.write( "----------------------------<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+-5t%5E2+%2B+22t+%2B+7.8+=+0+ ALIGN=MIDDLE  ALT=\"+-5t%5E2+%2B+22t+%2B+7.8+=+0+\"   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+-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+=+-5+ ALIGN=MIDDLE  ALT=\"+a+=+-5+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+22+ ALIGN=MIDDLE  ALT=\"+b+=+22+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+7.8+ ALIGN=MIDDLE  ALT=\"+c+=+7.8+\"   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+-22+%2B-+sqrt%28+22%5E2+-+4%2A%28-5%29%2A7.8+%29%29+%2F+%282%2A%28-5%29%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-22+%2B-+sqrt%28+22%5E2+-+4%2A%28-5%29%2A7.8+%29%29+%2F+%282%2A%28-5%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+-22+%2B-+sqrt%28+484+%2B+156+%29%29+%2F+%28-10%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-22+%2B-+sqrt%28+484+%2B+156+%29%29+%2F+%28-10%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+-22+%2B-+sqrt%28+640+%29%29+%2F+%28-10%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-22+%2B-+sqrt%28+640+%29%29+%2F+%28-10%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+-22+-+8%2Asqrt%2810%29+%29+%2F+%28-10%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-22+-+8%2Asqrt%2810%29+%29+%2F+%28-10%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+=+2.2+%2B+.8%2Asqrt%2810%29+ ALIGN=MIDDLE  ALT=\"+t+=+2.2+%2B+.8%2Asqrt%2810%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+=+2.2+%2B+.8%2A3.1623+ ALIGN=MIDDLE  ALT=\"+t+=+2.2+%2B+.8%2A3.1623+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+2.2+%2B+2.53+ ALIGN=MIDDLE  ALT=\"+t+=+2.2+%2B+2.53+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+4.73+ ALIGN=MIDDLE  ALT=\"+t+=+4.73+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The ball lands in 4.73 sec<BR>\n" );
document.write( "Note that I chose the largest positive root as the<BR>\n" );
document.write( "correct one for when the ball will land<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%2C+400%2C+-1%2C+6%2C+-5%2C+35%2C+-5x%5E2+%2B+22x+%2B+7.8+%29+ ALIGN=MIDDLE  ALT=\"+graph%28+400%2C+400%2C+-1%2C+6%2C+-5%2C+35%2C+-5x%5E2+%2B+22x+%2B+7.8+%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+ ALIGN=MIDDLE  ALT=\"+t+\"   DISABLED_style= \"max-width:90%; height:auto;\" > at <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+h+=+0+ ALIGN=MIDDLE  ALT=\"+h+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" > looks pretty close to <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+4.73+ ALIGN=MIDDLE  ALT=\"+4.73+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );