document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=30452>Question 30452</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Define variables and write a system of equations for each situation.  Solve by using substitution.\r<BR>\n" );
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document.write( "Suppose you want to join a video store. Big Video offers a special discount card that costs $9.99 for one year.  With the discount card, each video rental costs $2.49.  A discount card from Main Street Video cost $20.49 for one year.  With the Main Street Video discout card, each video rental costs $1.79. After how many video rentals is the cost the same? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #17097 by </B><A HREF=/tutors/aboutme.mpl?userid=mbarugel><B>mbarugel(146)</B></A><img src=\"/images/stars/stars-09.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mbarugel><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=17097\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let's call X to the number of video rentals you make.\r<BR>\n" );
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document.write( "If you go with the Big Video card, your total cost will be:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=Cost+=+9.99+%2B+2.49X ALIGN=MIDDLE  ALT=\"Cost+=+9.99+%2B+2.49X\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "If you go with Main Street video card, your total cost will be:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=Cost+=+20.49+%2B+1.79X ALIGN=MIDDLE  ALT=\"Cost+=+20.49+%2B+1.79X\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "So the system of equations is:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=Cost+=+9.99+%2B+2.49X ALIGN=MIDDLE  ALT=\"Cost+=+9.99+%2B+2.49X\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=Cost+=+20.49+%2B+1.79X ALIGN=MIDDLE  ALT=\"Cost+=+20.49+%2B+1.79X\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Substituting the 2nd equation into the 1st one, we get:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9.99+%2B+2.49X+=+20.49+%2B+1.79X ALIGN=MIDDLE  ALT=\"9.99+%2B+2.49X+=+20.49+%2B+1.79X\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2.49X+-+1.79X+=+20.49+-+9.99 ALIGN=MIDDLE  ALT=\"2.49X+-+1.79X+=+20.49+-+9.99\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.7X+=+10.5 ALIGN=MIDDLE  ALT=\"0.7X+=+10.5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=X+=+10.5%2F0.7+=+15 ALIGN=MIDDLE  ALT=\"X+=+10.5%2F0.7+=+15\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "The cost will be the same after 15 video rentals. </SPAN>\n" );
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