document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1102904>Question 1102904</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Solve the problem using the substitution method<BR>\n" );
document.write( "7x-9y=-8<BR>\n" );
document.write( "3x-y=16<BR>\n" );
document.write( "What is the solution set for x and y? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #717638 by </B><A HREF=/tutors/aboutme.mpl?userid=Gerwally><B>Gerwally(2)</B></A><img src=\"/images/stars/iconNewId_16x16.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Gerwally><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=717638\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The easiest way is to use the 2nd equation and solve for y. This avoids working with fractions.<BR>\n" );
document.write( "Adding y to both sides gives 3x=16+y, and then subtracting 16 from both sides gives y=3x-16. <BR>\n" );
document.write( "Substitute this value for y in the first equation, getting 7x-9(3x-16)=-8. Multiplying you get<BR>\n" );
document.write( "7x-27x+144=-8, then -20x+144=-8. Subtract 144 from both sides gives -20x=-152, then dividing both sides by -20 gives x=7.6.  Substitute 7.6 for x in first equation gives 7(7.6)-9y=-8, then multiplying gives 53.2-9y=-8 Subtract 53.2 from both sides leaves -9y=-8-53.2 or -9y=-61.2 Dividing both sides by -9 gives y=6.8 solution is x=7.6 and y=6.8<BR>\n" );
document.write( "Check:  Substitute both values into each equation. 7x-9y=-8 or 7(7.6)-9(6.8)-8 0r 53.2-61.2=-8 0r <BR>\n" );
document.write( "-8=-8. Check!  In second equation 3x-y=16 substitute 3(7.6)-6.8=16 or 22.8-6.8=16 or 16=16 Check! </SPAN>\n" );
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