document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=102507>Question 102507</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Solve the system by substitution.<BR>\n" );
document.write( "	x + y = 12<BR>\n" );
document.write( "	      y = 2x<BR>\n" );
document.write( "Again I need help with this problem. I also need help with showing how the problem is done step- by- step. Then maybe I can actually figure out how to figure these things out by myself, please, and thank you!! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #74536 by </B><A HREF=/tutors/aboutme.mpl?userid=doukungfoo><B>doukungfoo(195)</B></A><img src=\"/images/stars/stars-09.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=doukungfoo><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=doukungfoo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=74536\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> x + y = 12<BR>\n" );
document.write( "y = 2x<BR>\n" );
document.write( "Ok we have a system of equations here. To solve by substitution we are going to use information from the second equation and substitute it into the first equation.<BR>\n" );
document.write( "So here is the first equation:<BR>\n" );
document.write( "x + y = 12<BR>\n" );
document.write( "now since the 2nd equation tells us that y is equal to 2x let substitute that in<BR>\n" );
document.write( "so<BR>\n" );
document.write( "x + y = 12 becomes<BR>\n" );
document.write( "x + 2x = 12<BR>\n" );
document.write( "now we have an equation with only one variable to solve for <BR>\n" );
document.write( "so lets solve it<BR>\n" );
document.write( "x + 2x = 12<BR>\n" );
document.write( "combine x and 2x to get 3x<BR>\n" );
document.write( "3x = 12<BR>\n" );
document.write( "divide both sides by 3<BR>\n" );
document.write( "3x/3 = 12/3<BR>\n" );
document.write( "x = 4<BR>\n" );
document.write( "<b>Answer: We found that x = 4</b><BR>\n" );
document.write( "now use this value for x in ethier equation to solve for y<BR>\n" );
document.write( "so lets use the 2nd equation<BR>\n" );
document.write( "y = 2x<BR>\n" );
document.write( "sub in 4 for the x<BR>\n" );
document.write( "y = 2*4<BR>\n" );
document.write( "y = 8<BR>\n" );
document.write( "<b>Answer: Now we found y = 8</b><BR>\n" );
document.write( "Check both answers in both equations<BR>\n" );
document.write( "1st equation:<BR>\n" );
document.write( "x + y = 12<BR>\n" );
document.write( "4 + 8 = 12<BR>\n" );
document.write( "12 = 12<BR>\n" );
document.write( "that works now try the 2nd equation<BR>\n" );
document.write( "y = 2x<BR>\n" );
document.write( "8 = 2*4<BR>\n" );
document.write( "8 = 8<BR>\n" );
document.write( "That works too. So now we can be sure that we have sucessfully solve the system of equations.\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );