document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1171333>Question 1171333</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Given the parabola<BR>\n" );
document.write( "(x+2)^2=-8(y-5), which of the following is the vertex and directrix?<BR>\n" );
document.write( "The directrix is  y=0  and the vertex is  (-2,5)\r<BR>\n" );
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document.write( "The directrix is  y=-4  and the vertex is  (-2,5)\r<BR>\n" );
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document.write( "The directrix is  y=7  and the vertex is  (-2,5)\r<BR>\n" );
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document.write( "The directrix is  y=3  and the vertex is  (-2,5) </SPAN>\n" );
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document.write( "The given equation is in vertex form,<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28x-h%29%5E2=%284p%29%28y-k%29 ALIGN=MIDDLE  ALT=\"%28x-h%29%5E2=%284p%29%28y-k%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "where the vertex is (h,k) and p is the directed distance from the directrix to the vertex.<br><BR>\n" );
document.write( "With the given equation, then, you can see immediately that the vertex (h,k) is (-2,5) and 4p=-8 so p is -2.<br><BR>\n" );
document.write( "Since p is the directed distance from the directrix to the vertex, p=-2 means the directrix is 2 units ABOVE the vertex, because it is 2 units down from the directrix to the vertex.  So the directrix is at y=5+2=7.<br><BR>\n" );
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