document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=308561>Question 308561</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Problem: A rock is thrown from the top of a tall building. The distance, in feet, between the rock and the ground (T) seconds after it is thrown is given by d=-16Tsquared-2T+369. How long after the rock is thrown is it 330 feet from the ground?\r<BR>\n" );
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document.write( "I wrote the equation over again and replaced d as 330, making it 330=-16Tsquared-2T+369. I don't even know if this is what I'm supposed to be doing! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #220633 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=220633\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Problem: A rock is thrown from the top of a tall building. The distance, in feet, between the rock and the ground (T) seconds after it is thrown is given by d=-16Tsquared-2T+369. How long after the rock is thrown is it 330 feet from the ground? <BR>\n" );
document.write( "I wrote the equation over again and replaced d as 330, making it 330=-16Tsquared-2T+369. I don't even know if this is what I'm supposed to be doing!<BR>\n" );
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document.write( "That's the right approach.  Just solve for t<BR>\n" );
document.write( "330 = -16t^2 - 2t + 369<BR>\n" );
document.write( "-16t^2 - 2t + 39 = 0<BR>\n" );
document.write( "(8t + 13)*(-2t + 3) = 0<BR>\n" );
document.write( "t = -13/8 (Ignore it)<BR>\n" );
document.write( "t = 3/2 seconds<BR>\n" );
document.write( "It takes it 1.5 seconds to fall to 330 feet.<BR>\n" );
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