document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=539195>Question 539195</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A circle is Defined by the following equation,<BR>\n" );
document.write( "3x^2+3y^2-30x+27=0.<BR>\n" );
document.write( "what is the radius? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #353366 by </B><A HREF=/tutors/aboutme.mpl?userid=htmentor><B>htmentor(1343)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=htmentor><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=htmentor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=353366\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The equation for a circle in standard form is:<BR>\n" );
document.write( "(x-a)^2 + (y-b)^2 = R^2<BR>\n" );
document.write( "First, we can divide through by 3 which gives:<BR>\n" );
document.write( "x^2 + y^2 - 10x + 9 = 0<BR>\n" );
document.write( "In this case, we know b=0 since there is no linear term in y<BR>\n" );
document.write( "The coefficient of the linear x term is -10, which is obtained from (x-5)(x-5)<BR>\n" );
document.write( "So we can write<BR>\n" );
document.write( "(x-5)^2 + y^2 = R^2<BR>\n" );
document.write( "x^2 - 10x + 25 - R^2 + y^2 = 0 <-> x^2 - 10x + 9 + y^2 = 0<BR>\n" );
document.write( "This means 25 - R^2 = 9 -> R^2 = 16<BR>\n" );
document.write( "So the radius, R = 4<BR>\n" );
document.write( "And the equation in standard form is:<BR>\n" );
document.write( "(x-5)^2 + y^2 = 16<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );