document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=252367>Question 252367</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Suppose that x and y are real numbers such that 4^x / 2^x+y = 8   and\r<BR>\n" );
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document.write( "9^x+y / 3^5y = 243 Which of the following is equal to xy?\r<BR>\n" );
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document.write( "(a) -1    b 12/5    c 4    d 6     e 12\r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #184216 by </B><A HREF=/tutors/aboutme.mpl?userid=palanisamy><B>palanisamy(496)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=palanisamy><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=184216\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Given,    4^x / 2^x+y = 8<BR>\n" );
document.write( "          2^2x /2^x+y = 2^3<BR>\n" );
document.write( "          2^(2x-x-y)  = 2^3<BR>\n" );
document.write( "          2^(x-y)     = 2^3<BR>\n" );
document.write( "Therefore,       x-y  = 3   ...(1)\r<BR>\n" );
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document.write( "Next,    9^(x+y) / 3^5y = 243<BR>\n" );
document.write( "         3^2(x+y)/3^5y  = 3^5<BR>\n" );
document.write( "         3^(2x+2y-5y)   = 3^5<BR>\n" );
document.write( "         3^(2x-3y)      = 3^5<BR>\n" );
document.write( "Therefore,       2x-3y  = 5   ...(2)<BR>\n" );
document.write( "Solving (1) and (2),<BR>\n" );
document.write( "2x(1)-(2):<BR>\n" );
document.write( "          (2x-2y)-(2x-3y) = 6-5<BR>\n" );
document.write( "                        y = 1<BR>\n" );
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