document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=315583>Question 315583</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Roberto invested some money at 8%, and then invested $3000 more than twice this amount at 9%. HIs total annual income from the two investments was $3130. How much was invested at 9%? A)$25,000 B)$2500 C)$22,000 D)$9000\r<BR>\n" );
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document.write( "I tried by setting my values as follows:<BR>\n" );
document.write( "X=.08X<BR>\n" );
document.write( "Y=.09Y+3000(.08X)<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #225852 by </B><A HREF=/tutors/aboutme.mpl?userid=Fombitz><B>Fombitz(32388)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Fombitz><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=Fombitz><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=225852\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> OK, first name your variables.<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A ALIGN=MIDDLE  ALT=\"A\"   DISABLED_style= \"max-width:90%; height:auto;\" > be the amount at 8%,<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+B ALIGN=MIDDLE  ALT=\"+B\"   DISABLED_style= \"max-width:90%; height:auto;\" > the amount at 9%. <BR>\n" );
document.write( "You know the relationship between A and B. <BR>\n" );
document.write( "1.<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=B=3000%2B2A ALIGN=MIDDLE  ALT=\"B=3000%2B2A\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Also you know the total interest from both of the investments.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.08A%2B0.09B=3130 ALIGN=MIDDLE  ALT=\"0.08A%2B0.09B=3130\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply both side by 100 to get rid of decimals.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=8A%2B9B=313000 ALIGN=MIDDLE  ALT=\"8A%2B9B=313000\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Substitute eq. 1 into eq. 2 and solve for A.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=8A%2B9%283000%2B2A%29=313000 ALIGN=MIDDLE  ALT=\"8A%2B9%283000%2B2A%29=313000\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=8A%2B27000%2B18A=313000 ALIGN=MIDDLE  ALT=\"8A%2B27000%2B18A=313000\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=26A=286000 ALIGN=MIDDLE  ALT=\"26A=286000\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28+A=11000%29 ALIGN=MIDDLE  ALT=\"highlight%28+A=11000%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Then from eq. 1,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=B=3000%2B2%2811000%29 ALIGN=MIDDLE  ALT=\"B=3000%2B2%2811000%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=B=3000%2B22000 ALIGN=MIDDLE  ALT=\"B=3000%2B22000\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28+B=25000%29 ALIGN=MIDDLE  ALT=\"highlight%28+B=25000%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );