document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=402749>Question 402749</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a student dropped his cell phone from a floor with a height of 81 feet. the heigh of the phone after t seconds is given by the quadradic equation h=-9t^2+81. how long will it take for the cell phone to hit the ground? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #284881 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=284881\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a student dropped his cell phone from a floor with a height of 81 feet. the heigh of the phone after t seconds is given by the quadradic equation h=-9t^2+81. how long will it take for the cell phone to hit the ground?<BR>\n" );
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document.write( "Set h to 0 and solve for t:<BR>\n" );
document.write( "h=-9t^2+81<BR>\n" );
document.write( "0=-9t^2+81<BR>\n" );
document.write( "-81=-9t^2<BR>\n" );
document.write( "9 = t^2<BR>\n" );
document.write( "3 seconds = t\r<BR>\n" );
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document.write( " </SPAN>\n" );
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