document.write( "Question 679923: solve for x
\n" ); document.write( "ln x + ln(x+4)=0
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Algebra.Com's Answer #422128 by stanbon(75887) $\"\"$ $\"About$

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ln x + ln(x+4)=0
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\n" ); document.write( "ln[x(x+4)] = 0
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\n" ); document.write( "x(x+4) = 10^0
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\n" ); document.write( "x^2+4x = 1
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\n" ); document.write( "x^2+4x-1 = 0
\n" ); document.write( "Use the quadratic formula:
\n" ); document.write( "x = [-4 +- sqrt(16-4*(-1)]/2
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\n" ); document.write( "x = [-4 +- sqrt(20)]/2
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\n" ); document.write( "x = [-2 +- 2sqrt(5)]
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\n" ); document.write( "Positive solution:
\n" ); document.write( "x = -2 + 2sqrt(5) = 2.4721...
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "

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