document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1176570>Question 1176570</A>: <I><SPAN STYLE=\"word-break: break-all;\"> State the focus of Parabola where the equation in y=-16x^2<BR>\n" );
document.write( "a) 4<BR>\n" );
document.write( "b) 16<BR>\n" );
document.write( "c) -8<BR>\n" );
document.write( "d) -4<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 #803718 by </B><A HREF=/tutors/aboutme.mpl?userid=Solver92311><B>Solver92311(821)</B></A><img src=\"/images/stars/stars-11.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Solver92311><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=Solver92311><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=803718\">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( "None of the answers given represent the focus of the given parabola.  A focus of a parabola is a point.  A parabola that is defined by an equation that contains two variables has a focus that is only correctly identified by an ordered pair.  The given answers are simply numbers.  Had you asked for the <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large y\">-coordinate of the focus, you still would be out of luck because <i>that</i> answer isn't on the list either.\r<BR>\n" );
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document.write( "For a vertex form equation of a parabola with a vertical axis of symmetry, such as the one that you were given is:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \ \ \ \ \ \ \ \ \ \ y\ =\ a(x\,-\,h)\,+\,k\">\r<BR>\n" );
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document.write( "For this parabola, the vertex is at <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large (h,k)\">, the focus is at <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large \(h,k\,+\,\frac{1}{4a}\)\">, and the equation of the directrix is <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large y\ =\ k\ -\ \frac{1}{4a}\">.\r<BR>\n" );
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document.write( "You can do your own arithmetic to find the focus of your parabola.\r<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( "From <https://www.algebra.com/cgi-bin/upload-illustration.mpl> <BR>\n" );
document.write( "I > Ø<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large \ \\r\"> </SPAN>\n" );
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