document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=967064>Question 967064</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Ricardo throws a stone off a bridge into a river below. The stone's height above the water in meters, y, is dependent on time in seconds after throwing, x, and can be modeled with the function y=&#8722;5(x&#8722;8)(x+4).\r<BR>\n" );
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document.write( "How many seconds after being thrown will the stone hit the water? seconds\r<BR>\n" );
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document.write( "What is the maximum height that the stone will reach? meters\r<BR>\n" );
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document.write( "How many seconds after being thrown will the stone reach its maximum height?  seconds \r<BR>\n" );
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document.write( "What is the height of the stone at the time it is thrown?  meters<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #591053 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=591053\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Ricardo throws a stone off a bridge into a river below. The stone's height above the water in meters, y, is dependent on time in seconds after throwing, x, and can be modeled with the function <BR>\n" );
document.write( "y=&#8722;5(x&#8722;8)(x+4)<BR>\n" );
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document.write( "y = -5(x^2 -4x -32) = -5x^2 + 20x + 160<BR>\n" );
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document.write( " How many seconds after being thrown will the stone hit the water? seconds<BR>\n" );
document.write( "Solve -5(x-8)(x+4) = 0<BR>\n" );
document.write( "Ans: x = 8 seconds<BR>\n" );
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document.write( "What is the maximum height that the stone will reach? meters<BR>\n" );
document.write( "Vertex occurs at x = -b/(2a) = -20/(-10) = 2 seconds<BR>\n" );
document.write( "Max height = f(2) = -5(-6)(6) = 180 meters<BR>\n" );
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document.write( "How many seconds after being thrown will the stone reach its maximum height? seconds<BR>\n" );
document.write( "Ans: 2 seconds (from vertex work above)<BR>\n" );
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document.write( "What is the height of the stone at the time it is thrown? <BR>\n" );
document.write( "Ans: f(0) = 160 meters<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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