document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=452224>Question 452224</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 3x+9y=21<BR>\n" );
document.write( "-8x=y=19<BR>\n" );
document.write( "I am hoping to get some help with this, I am trying to solve by the substitution method, I am being told to solve the second equation first, but i do not understand why. Thank you so much for any help that you can give  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #310851 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=310851\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 3x+9y=21<BR>\n" );
document.write( "-8x+y=19<BR>\n" );
document.write( "--------<BR>\n" );
document.write( "You assume the x's mean the same in both<BR>\n" );
document.write( "equations and the y's mean the same in<BR>\n" );
document.write( "both equations.<BR>\n" );
document.write( "-----<BR>\n" );
document.write( "So you solve one of the equations for one of <BR>\n" );
document.write( "the variables:<BR>\n" );
document.write( "For example: y = 8x+19<BR>\n" );
document.write( "-----<BR>\n" );
document.write( "You substitute that expression into the other<BR>\n" );
document.write( "equation in place of \"y\" to get an equation<BR>\n" );
document.write( "with only the variable \"x\".<BR>\n" );
document.write( "---<BR>\n" );
document.write( "3x + 9*(8x+19) = 21<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Divide thru by 3 to get:<BR>\n" );
document.write( "x + 3(8x+19) = 7<BR>\n" );
document.write( "x + 24x + 57 = 7<BR>\n" );
document.write( "25x = -50<BR>\n" );
document.write( "x = -2<BR>\n" );
document.write( "-----<BR>\n" );
document.write( "Now you can solve for \"y\":<BR>\n" );
document.write( "y = 8x+19<BR>\n" );
document.write( "y = 8*(-2)+19<BR>\n" );
document.write( "y = -16+19<BR>\n" );
document.write( "y = 3<BR>\n" );
document.write( "--------<BR>\n" );
document.write( "Solution for the system of two equations: (-2,3)<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" );