document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1010711>Question 1010711</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I am stuck on this problem.  If I can see this worked out it would help a lot!\r<BR>\n" );
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document.write( "If f(x) = (1/x - 9x) / (1+3x), what is f(1/x).\r<BR>\n" );
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document.write( "My book says the answer is x-3 but I cannot get this same answer. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #626188 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=626188\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> problem is:\r<BR>\n" );
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document.write( "f(x) = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%281%2Fx+-+9x%29+%2F+%281+%2B+3x%29 ALIGN=MIDDLE  ALT=\"%281%2Fx+-+9x%29+%2F+%281+%2B+3x%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "what is f(1/x)\r<BR>\n" );
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document.write( "you replace x with 1/x and the equation becomes:\r<BR>\n" );
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document.write( "f(x) = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%281%2F%281%2Fx%29+-+9%2A1%2Fx%29+%2F+%281+%2B+3%2A%281%2Fx%29%29 ALIGN=MIDDLE  ALT=\"%281%2F%281%2Fx%29+-+9%2A1%2Fx%29+%2F+%281+%2B+3%2A%281%2Fx%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "1/(1/x) = 1*x = x<BR>\n" );
document.write( "9*1/x = 9/x<BR>\n" );
document.write( "3*(1/x) = 3/x\r<BR>\n" );
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document.write( "equation becomes:\r<BR>\n" );
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document.write( "f(1/x) = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28x-9%2Fx%29+%2F+%281+%2B+3%2Fx%29 ALIGN=MIDDLE  ALT=\"%28x-9%2Fx%29+%2F+%281+%2B+3%2Fx%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "multiply numerator and denominator of this equation by x to get:\r<BR>\n" );
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document.write( "f(1/x) = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28x%5E2-9%29+%2F+%28x+%2B+3%29 ALIGN=MIDDLE  ALT=\"%28x%5E2-9%29+%2F+%28x+%2B+3%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "x^2 - 9 = (x-3) * (x+3)\r<BR>\n" );
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document.write( "equation becomes:\r<BR>\n" );
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document.write( "f(1/x) = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28%28x%2B3%29%2A%28x-3%29%29+%2F+%28x%2B3%29 ALIGN=MIDDLE  ALT=\"%28%28x%2B3%29%2A%28x-3%29%29+%2F+%28x%2B3%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "the x+3 in the numerator and in the denominator cancel out and you are left with:\r<BR>\n" );
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document.write( "f(1/x) = (x-3)\r<BR>\n" );
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document.write( " </SPAN>\n" );
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