document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=734832>Question 734832</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Solve for x and y by deriving an expression for y from the second equation, and substituting it back into the first equation.\r<BR>\n" );
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document.write( "&#8722;5x&#8722;7y=9<BR>\n" );
document.write( "6x+9y=-9<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 #449152 by </B><A HREF=/tutors/aboutme.mpl?userid=checkley79><B>checkley79(3341)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=checkley79><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=449152\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> &#8722;5x&#8722;7y=9<BR>\n" );
document.write( "6x+9y=-9<BR>\n" );
document.write( "9y=-6x-9<BR>\n" );
document.write( "y=(-6x-9)/9<BR>\n" );
document.write( "-5x-7(-6x-9)/9=-9<BR>\n" );
document.write( "-5x+(42x+63)/9=-9<BR>\n" );
document.write( "(-5x*9+42x+63)/9=-9<BR>\n" );
document.write( "(-45x+42x+63)=-9*9<BR>\n" );
document.write( "-3x+63=-81<BR>\n" );
document.write( "-3x=-81-63<BR>\n" );
document.write( "-3x=-144<BR>\n" );
document.write( "x=-144/-3<BR>\n" );
document.write( "x=48 ans.<BR>\n" );
document.write( "y=(-6*48-9)/9<BR>\n" );
document.write( "y=(-288-9)/9<BR>\n" );
document.write( "y=-297/9<BR>\n" );
document.write( "y=33 ans.<BR>\n" );
document.write( "Proof:<BR>\n" );
document.write( "5*48-7*33=9<BR>\n" );
document.write( "240-231=9<BR>\n" );
document.write( "9=9\r<BR>\n" );
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document.write( " </SPAN>\n" );
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