document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1160555>Question 1160555</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A person standing close to the edge on top of a 40 foot building throws a bal vertically upward. The quadratic function h(t)= -16t^2 +72t + 40 models the ball's height about the ground, h(t), in feet, t seconds after it was thrown.\r<BR>\n" );
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document.write( "What is the maximum height of the ball?\r<BR>\n" );
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document.write( "How many seconds does it take until the ball hits 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 #783857 by </B><A HREF=/tutors/aboutme.mpl?userid=solver91311><B>solver91311(24713)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=solver91311><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=solver91311><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=783857\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <font face=\"Times New Roman\" size=\"+2\">\r<BR>\n" );
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document.write( "The maximum height is at the vertex of the parabola described by the quadratic function.\r<BR>\n" );
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document.write( "The vertex of <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \rho(x)\ =\ ax^2\ +\ bx\ +\ c\">\r<BR>\n" );
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document.write( "is at <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \(\frac{-b}{2a},\,\rho\(\frac{-b}{2a}\)\)\">.  For your height function, the maximum height is the <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large y\">-coordinate of the vertex point.\r<BR>\n" );
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document.write( "The height of the ball when it hits the ground is zero feet.  Solve:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \ \ \ \ \ \ \ \ \ \ -16t^2\ +\ 72t\ +\ 40\ =\ 0\">\r<BR>\n" );
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document.write( "for the positive root.<BR>\n" );
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document.write( "John<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE e^{i\pi}\ +\ 1\ =\ 0\"><BR>\n" );
document.write( "My calculator said it, I believe it, that settles it<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large \ \\r\"> </SPAN>\n" );
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