document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=243032>Question 243032</A>: <I><SPAN STYLE=\"word-break: break-all;\"> solve using any appropriate method. Full work out please.<BR>\n" );
document.write( "2.1x - 0.9y =15<BR>\n" );
document.write( "-1.4x + 0.6y=10 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #178050 by </B><A HREF=/tutors/aboutme.mpl?userid=oberobic><B>oberobic(2304)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=oberobic><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=178050\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> First, multiply everything by 10 to get rid of the decimals.<BR>\n" );
document.write( "EQ. 1:  21x - 9y = 150<BR>\n" );
document.write( "EQ. 2:  -14x + 6y = 100<BR>\n" );
document.write( "...<BR>\n" );
document.write( "Divide EQ. 1 by 3:  7x - 3y = 50<BR>\n" );
document.write( "Divide EQ. 2 by 2: -7x + 3y = 50<BR>\n" );
document.write( "...<BR>\n" );
document.write( "This is a disturbing pair of equations because they are just too similar.<BR>\n" );
document.write( "Consider -7x + 3y = 50 can be written as -(7x - 3y) = 50.<BR>\n" );
document.write( "Given 50 = 50 (a tautology), we now can say:<BR>\n" );
document.write( "7x - 3y = -(7x - 3y), which seems a contradiction in terms.<BR>\n" );
document.write( "...<BR>\n" );
document.write( "Perhaps they're parallel, in which case there is no solution.  <BR>\n" );
document.write( "We can test this theory putting them in slope intercept form.<BR>\n" );
document.write( "...<BR>\n" );
document.write( "EQ 1.<BR>\n" );
document.write( "7x - 3y = 50<BR>\n" );
document.write( "-3y = -7x + 50<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=%28-7%2F-3%29x+%2B+%2850%2F-3%29 ALIGN=MIDDLE  ALT=\"y+=%28-7%2F-3%29x+%2B+%2850%2F-3%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "which is simply...<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+%287%2F3%29x+-+50%2F3 ALIGN=MIDDLE  ALT=\"y+=+%287%2F3%29x+-+50%2F3\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "...<BR>\n" );
document.write( "EQ 2.<BR>\n" );
document.write( "-7x + 3y = 50<BR>\n" );
document.write( "3y = 7x + 50<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+%287%2F3%29x+%2B+50%2F3 ALIGN=MIDDLE  ALT=\"y+=+%287%2F3%29x+%2B+50%2F3\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "...<BR>\n" );
document.write( "So we have parallel lines, so there is no solution to the system of equations. </SPAN>\n" );
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