document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=637693>Question 637693</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A kicker starts a football game by \"kicking off\".  The quadratic function y = -12&#8901;x2 + 36&#8901;x models the football's height after x seconds.  How long is the football in the air? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #401844 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=401844\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A kicker starts a football game by \"kicking off\".<BR>\n" );
document.write( " The quadratic function y = -12&#8901;x2 + 36&#8901;x models the football's height after x seconds.<BR>\n" );
document.write( " How long is the football in the air?<BR>\n" );
document.write( ":<BR>\n" );
document.write( "y = -12x^2 + 36x<BR>\n" );
document.write( "When the ball hits the ground, y = 0; therefore:<BR>\n" );
document.write( "-12x^2 + 36x = 0<BR>\n" );
document.write( "Factor out -12x<BR>\n" );
document.write( "-12x(x - 3) = 0<BR>\n" );
document.write( "Two solutions<BR>\n" );
document.write( "x = 0<BR>\n" );
document.write( "and<BR>\n" );
document.write( "x = 3 seconds in the air </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );