document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1098932>Question 1098932</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The height in feet, h, reached by a softball after t seconds is given by the function <BR>\n" );
document.write( "h(t) = &#8722;16t2 + 87t + 3.<BR>\n" );
document.write( " During what time interval did the softball reach an altitude of at least 80 ft? Round to 2 decimal places. (Enter your answer using interval notation.) <BR>\n" );
document.write( "The answer I came up with was [.18,5.26]<BR>\n" );
document.write( "My teacher looked and doesn't know why the computer counted this wrong.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #713330 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=713330\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I'll try it:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+h%28t%29+=+-16t%5E2+%2B+87t+%2B+3+ ALIGN=MIDDLE  ALT=\"+h%28t%29+=+-16t%5E2+%2B+87t+%2B+3+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+80+=+-16t%5E2+%2B+87t+%2B+3+ ALIGN=MIDDLE  ALT=\"+80+=+-16t%5E2+%2B+87t+%2B+3+\"   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+87t+-+77+=+0+ ALIGN=MIDDLE  ALT=\"+-16t%5E2+%2B+87t+-+77+=+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+=+-16+ ALIGN=MIDDLE  ALT=\"+a+=+-16+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+87+ ALIGN=MIDDLE  ALT=\"+b+=+87+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+-77+ ALIGN=MIDDLE  ALT=\"+c+=+-77+\"   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+-87+%2B-+sqrt%28+87%5E2-4%2A%28-16%29%2A%28-77%29+%29%29%2F%282%2A%28-16%29%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-87+%2B-+sqrt%28+87%5E2-4%2A%28-16%29%2A%28-77%29+%29%29%2F%282%2A%28-16%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+-87+%2B-+sqrt%28+7569+-+4928+%29+%29+%2F+%28+-32+%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-87+%2B-+sqrt%28+7569+-+4928+%29+%29+%2F+%28+-32+%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+-87+%2B-+sqrt%28+2641+%29+%29+%2F+%28+-32+%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-87+%2B-+sqrt%28+2641+%29+%29+%2F+%28+-32+%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+-87+%2B+51.39067+%29+%2F+%28-32+%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-87+%2B+51.39067+%29+%2F+%28-32+%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+=+-35.60934+%2F+%28-32%29+ ALIGN=MIDDLE  ALT=\"+t+=+-35.60934+%2F+%28-32%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+=+1.1128+ ALIGN=MIDDLE  ALT=\"+t+=+1.1128+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "and<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28+-87+-+51.39067+%29+%2F+%28-32%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-87+-+51.39067+%29+%2F+%28-32%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+=+-138.39067+%2F+%28+-32+%29+ ALIGN=MIDDLE  ALT=\"+t+=+-138.39067+%2F+%28+-32+%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+=+4.3247+ ALIGN=MIDDLE  ALT=\"+t+=+4.3247+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The softball reaches at least a height of 80 ft<BR>\n" );
document.write( "between 1.11 sec and 4.32 sec<BR>\n" );
document.write( "------------------------------------------<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "Here's the plot of h(t):<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+graph%28+400%2C400%2C+-1%2C+8%2C+-10%2C+130%2C+-16x%5E2+%2B+87x+%2B+3+%29+ ALIGN=MIDDLE  ALT=\"+graph%28+400%2C400%2C+-1%2C+8%2C+-10%2C+130%2C+-16x%5E2+%2B+87x+%2B+3+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "My answers look at least close<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );