document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=201509>Question 201509</A>: <I><SPAN STYLE=\"word-break: break-all;\"> ln(4x)=ln(x-5). Solve, can you please help me?<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 #151743 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=151743\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> this can only be true if 4x = x-5.\r<BR>\n" );
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document.write( "solve for x and you have the answer.\r<BR>\n" );
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document.write( "subtract x from both sides of the equation to get\r<BR>\n" );
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document.write( "4x - x = -5\r<BR>\n" );
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document.write( "simplify to get\r<BR>\n" );
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document.write( "3x = -5\r<BR>\n" );
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document.write( "divide both sides of the equation to get\r<BR>\n" );
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document.write( "x =  -5/3\r<BR>\n" );
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document.write( "that's your answer.\r<BR>\n" );
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document.write( "substitute in the equation to get\r<BR>\n" );
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document.write( "ln (4*(-5/3) = ln (-5/3 - 5)\r<BR>\n" );
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document.write( "simplify to get\r<BR>\n" );
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document.write( "ln (-20/3) = ln (-5/3 - 15/3)\r<BR>\n" );
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document.write( "simplify further to get\r<BR>\n" );
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document.write( "ln (-20/3) = ln (-20/3)\r<BR>\n" );
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document.write( "since this is an identity, it proves your answer is correct.\r<BR>\n" );
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document.write( "the problem I see here is that you are trying to take the natural log of a negative number.\r<BR>\n" );
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document.write( "all logs have to greater than 0.\r<BR>\n" );
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document.write( "negative numbers or 0 are not allowed.\r<BR>\n" );
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document.write( "if I have done this correctly, then the value of x is correct and the natural log cannot be found.\r<BR>\n" );
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document.write( "I used the calculator to try to get the answer but the calculator said the logarithm can't be found.\r<BR>\n" );
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document.write( "to prove the logic is correct, I'll give you one that can be found.\r<BR>\n" );
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document.write( "take ln (4x) = ln (x + 15)\r<BR>\n" );
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document.write( "this can only be true if 4x = x + 15\r<BR>\n" );
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document.write( "this is true if x = 5 because 4 * 5 = 5 + 15.\r<BR>\n" );
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document.write( "your answer would be x = 5 and you would have ln (20) = ln (20) which is an identify again only this time it can be solved.\r<BR>\n" );
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