document.write( "Question 183593: Solve
\n" ); document.write( "ln(4x+3)=ln(7x+9)\r
\n" ); document.write( "\n" ); document.write( "log5x+log(x-1)=2 \n" ); document.write( "
Algebra.Com's Answer #137818 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
Solve
\n" ); document.write( "ln(4x+3)=ln(7x+9)
\n" ); document.write( "4x+3 = 7x+9
\n" ); document.write( "3x = -6
\n" ); document.write( "x = -2
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\n" ); document.write( "Checking those values in the original equations you get:
\n" ); document.write( "ln(-8+3) = ln(-14+9)
\n" ); document.write( "ln(-5) = ln(-5)
\n" ); document.write( "That looks good but it isn't.
\n" ); document.write( "There are no natural logs of negative numbers.
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\n" ); document.write( "Your problem has no solution.
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\n" ); document.write( "log5x+log(x-1)=2
\n" ); document.write( "log[5x(x-1)] = 2\r
\n" ); document.write( "\n" ); document.write( "5x^2-5x = 10^2
\n" ); document.write( "5x^2 - 5x - 100 = 0
\n" ); document.write( "x^2 -x - 20 = 0
\n" ); document.write( "(x-5)(x+4) = 0
\n" ); document.write( "x = 5 or x = -4
\n" ); document.write( "---
\n" ); document.write( "x = 5 is a good solution; x = -4 just doesn't work in the original equation.
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.-\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
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