document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=743917>Question 743917</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find the vertx, the directrix, and the focus.<BR>\n" );
document.write( "(x-4)^2 = 4(y+1) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #453600 by </B><A HREF=/tutors/aboutme.mpl?userid=crazylogms><B>crazylogms(2)</B></A><img src=\"/images/stars/iconNewId_16x16.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=crazylogms><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=crazylogms><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=453600\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Given (x-4)^2 = 4(y+1)  ------------------> (1)\r<BR>\n" );
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document.write( "Comparing to (x-h)^2 = 4a(y-k) ------------------> (2)\r<BR>\n" );
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document.write( "(h,k) = (4,-1) ----------> Vertex \r<BR>\n" );
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document.write( "From (1) & (2),\r<BR>\n" );
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document.write( "4a = 4 ,[ a=1 ]\r<BR>\n" );
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document.write( "Equation of directrix y-k=-a,  y+1=-1, y=-2 --------> Equation of directrix\r<BR>\n" );
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document.write( "Vertex of Parabola (x-h=0, y-k=a)<BR>\n" );
document.write( "x=h     ,    y=a+k<BR>\n" );
document.write( "x=4     ,    y=0<BR>\n" );
document.write( "(4,0) ---------------------------------> Vertex of Parabola.\r<BR>\n" );
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document.write( "Cheers  </SPAN>\n" );
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