document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=45455>Question 45455</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0534493947/algebrahomeworkh>intermediate algebra</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> Sove the logarithmic equation, could you explain to me how to do this?\r<BR>\n" );
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document.write( "log x + log (x+9) = 1 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #30195 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=30195\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> log x + log (x+9) = 1\r<BR>\n" );
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document.write( "You have a log rule which says log a + log b = log ab\r<BR>\n" );
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document.write( "So, you write:\r<BR>\n" );
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document.write( " log x(x+9) =1\r<BR>\n" );
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document.write( "You know a transformation which says \r<BR>\n" );
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document.write( "log b = c means  the same as b=10^c\r<BR>\n" );
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document.write( "So you write:<BR>\n" );
document.write( "x(x+9)=10^1<BR>\n" );
document.write( "x^2+9x-10=0<BR>\n" );
document.write( "(x+10)(x-1)=0\r<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "x=-10 or x=1\r<BR>\n" );
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document.write( "You check these answers in the original equation<BR>\n" );
document.write( "and see that x=-10 cannot be a solution because you<BR>\n" );
document.write( "cannot have the log of a negative number.\r<BR>\n" );
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document.write( "So, x=1 is the only solution of your original equation.\r<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );