document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=145227>Question 145227</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find the foci of a hyperbola with the equation 9y2 - 72y - 16x2 - 64x - 64 = 0.<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 #105946 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=105946\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Find the foci of a hyperbola with the equation 9y2 - 72y - 16x2 - 64x - 64 = 0.<BR>\n" );
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document.write( "9(y^2 - 8y + 16) - 16(x^2 -4x + 4) = 64+9*16-4*16\r<BR>\n" );
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document.write( "9(y -4)^2 - 16(x - 2)^2 = 144\r<BR>\n" );
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document.write( "[(y -4)^2/16] - [(x - 2)^2/4]  = 1<BR>\n" );
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document.write( "Center at (2,4); a = 4 ; b = 2 ; therefore c = sqrt(a^2+b^2) = 2sqrt(5)<BR>\n" );
document.write( "Focus at (2, 4+2sqrt(5)) and (2,4-2sqrt(5))<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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