document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=256989>Question 256989</A>: <I><SPAN STYLE=\"word-break: break-all;\"> i don't understand how substitution works. can anyone explain to me in a easy way? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #189014 by </B><A HREF=/tutors/aboutme.mpl?userid=richwmiller><B>richwmiller(17219)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richwmiller><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=richwmiller><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=189014\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let's say you have two equations.<BR>\n" );
document.write( "a+b=10<BR>\n" );
document.write( "a+2b=16<BR>\n" );
document.write( "solve the first one for a in terms of b<BR>\n" );
document.write( "a=10-b<BR>\n" );
document.write( "now plug 10-b in for a in the other equation<BR>\n" );
document.write( "a+2b=16<BR>\n" );
document.write( "(10-b)+2b =16<BR>\n" );
document.write( "Do you see how I substituted 10-b for a because a=10-b?<BR>\n" );
document.write( "Now we can solve the new equation and find out what b is.<BR>\n" );
document.write( "10-b+2b=16<BR>\n" );
document.write( "combine -b and +2b<BR>\n" );
document.write( "-b+2b=b<BR>\n" );
document.write( "so now we have 10+b=16<BR>\n" );
document.write( "subtract 10 from both sides<BR>\n" );
document.write( "b=6<BR>\n" );
document.write( "but a+b=10<BR>\n" );
document.write( "so a+6=10<BR>\n" );
document.write( "a=4<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );