document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=98399>Question 98399</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I need the following please:\r<BR>\n" );
document.write( "\n" );
document.write( "standard form for:  x^2-4x-2y-8=0<BR>\n" );
document.write( "vertex and focus of the following parabola:  y^2+10y-x+3=0<BR>\n" );
document.write( "find the equation of the directrix of the parabola:  4x^2-8x-2y-4=0\r<BR>\n" );
document.write( "\n" );
document.write( "thanks for the help<BR>\n" );
document.write( "I have worked them - just not sure<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #71559 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=71559\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> standard form for: x^2-4x-2y-8=0<BR>\n" );
document.write( "2y = x^2-4x-8<BR>\n" );
document.write( "y = (1/2)x^2-2x-4<BR>\n" );
document.write( "------------------<BR>\n" );
document.write( "vertex and focus of the following parabola: y^2+10y-x+3=0<BR>\n" );
document.write( "x = y^2+10y+3<BR>\n" );
document.write( "Complete the square on the y terms:<BR>\n" );
document.write( "x-3+? = y^2+10y+?<BR>\n" );
document.write( "y^2+10y+25 = x-3+25<BR>\n" );
document.write( "(y+5)^2 = x+22<BR>\n" );
document.write( "------------------<BR>\n" );
document.write( "Vertex: (-22,-5)<BR>\n" );
document.write( "4p=1 so p=1/4<BR>\n" );
document.write( "The parabola opens to the right so <BR>\n" );
document.write( "focus = (-22+(1/4),-5) = (-87/4,-5)<BR>\n" );
document.write( "---------------------------------<BR>\n" );
document.write( "find the equation of the directrix of the parabola: 4x^2-8x-2y-4=0 <BR>\n" );
document.write( "Divde thru by 2 to get:<BR>\n" );
document.write( "2x^2-4x-y-2=0<BR>\n" );
document.write( "y+2 = 2x^2-4x<BR>\n" );
document.write( "y+2+2*? = 2(x^2-2x+?)<BR>\n" );
document.write( "2(x^2-2x+1) = y+2+2<BR>\n" );
document.write( "2(x-1)^2 = y+4<BR>\n" );
document.write( "(x-1)^2 = (1/2)(y+4)<BR>\n" );
document.write( "----------------<BR>\n" );
document.write( "Vertex = (1,-4)<BR>\n" );
document.write( "4p=(1/2)<BR>\n" );
document.write( "p = 1/8<BR>\n" );
document.write( "--------------<BR>\n" );
document.write( "Parabola opens up so directrix is p below the vertex.<BR>\n" );
document.write( "Directrix: y = -4-(1/8) = -33/8<BR>\n" );
document.write( "================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );