document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=74666>Question 74666</A>: <I><SPAN STYLE=\"word-break: break-all;\"> could someone help me with this problem?\r<BR>\n" );
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document.write( "the focus of the parabola 4y^2+12x-12y+39=0 is________?\r<BR>\n" );
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document.write( "how do i find this?  thanks for your help..it was a problem presented in class. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #53653 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=53653\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> the focus of the parabola 4y^2+12x-12y+39=0 is________? <BR>\n" );
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document.write( "You need to find the vertex and the value of \"p\".<BR>\n" );
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document.write( "Rewrite as 4y^2-12y =-12x-39<BR>\n" );
document.write( "Complete the square on the left side:<BR>\n" );
document.write( "4(y^2-3y+(3/2)^2) = -12x-39+4(3/2)^2<BR>\n" );
document.write( "4(y-(3/2))^2 = -12x-39+9<BR>\n" );
document.write( "(y-(3/2))^2 = -3x-30/4<BR>\n" );
document.write( "(y-(3/2))^2 = -3(x+(10/4))<BR>\n" );
document.write( "This is the form of a parabola opening to the left.<BR>\n" );
document.write( "So, the vertex is at (-10/4,(3/2))<BR>\n" );
document.write( "And 4p=-3 so p=-3/4<BR>\n" );
document.write( "Therefore the focus is at (-10/4-(3/4),3/2) or (-13/4,3/2)<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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