document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=130784>Question 130784</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If a rock falls from a height of 40 meters on Earth, the height H (in meters) after x seconds is approximately<BR>\n" );
document.write( "H(x) = 40 - 4.9x2. <BR>\n" );
document.write( "When does the rock strike the ground? Round to the nearest hundredth, if necessary.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #95483 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=95483\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If a rock falls from a height of 40 meters on Earth, the height H (in meters) after x seconds is approximately<BR>\n" );
document.write( "H(x) = 40 - 4.9x2. <BR>\n" );
document.write( "When does the rock strike the ground? Round to the nearest hundredth, if necessary. <BR>\n" );
document.write( "--------------<BR>\n" );
document.write( "Let H(x) = zero and solve for \"x\".<BR>\n" );
document.write( "40 - 4.9x^2 = 0<BR>\n" );
document.write( "4.9x^2 = 40<BR>\n" );
document.write( "x^2 = 40/4.9<BR>\n" );
document.write( "x^2 = 400/49<BR>\n" );
document.write( "x = 20/7<BR>\n" );
document.write( "x = 2.857...<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );