document.write( "Question 150019: solve for x.\r
\n" ); document.write( "\n" ); document.write( "2 log2 x - log2 (x+4)= log2 2 \n" ); document.write( "

Algebra.Com's Answer #110142 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
Logarithm rules
\n" ); document.write( " $\"log%28%28A%2AB%29%29=log%28A%29%2Blog%28B%29\"$
\n" ); document.write( " $\"log%28%28A%29%5EN%29=Nlog%28A%29\"$
\n" ); document.write( " $\"log%28%28A%2FB%29%29=log%28A%29-log%28B%29\"$
\n" ); document.write( ".
\n" ); document.write( ".
\n" ); document.write( ".
\n" ); document.write( " $\"2%2Alog%282%2Cx%29-log%282%2C%28x%2B4%29%29=log%282%2C2%29\"$
\n" ); document.write( " $\"log%282%2Cx%5E2%29-log%282%2C%28x%2B4%29%29=log%282%2C2%29\"$
\n" ); document.write( " $\"log%282%2C%28x%5E2%2F%28x%2B4%29%29%29=log%282%2C2%29\"$
\n" ); document.write( "Take the inverse log of both sides.
\n" ); document.write( " $\"x%5E2%2F%28x%2B4%29=2\"$
\n" ); document.write( " $\"x%5E2=2%28x%2B4%29\"$
\n" ); document.write( " $\"x%5E2=2x%2B8\"$
\n" ); document.write( " $\"x%5E2-2x-8=0\"$
\n" ); document.write( " $\"x-4%29%28x%2B2%29=0\"$
\n" ); document.write( "First solution
\n" ); document.write( " $\"x-4=0\"$
\n" ); document.write( " $\"x=4\"$
\n" ); document.write( "Second solution
\n" ); document.write( " $\"x%2B2=0\"$
\n" ); document.write( " $\"x=-2\"$
\n" ); document.write( "Second solution is not allowed since $\"log%282%2C%28-2%29%29\"$ is not defined.
\n" ); document.write( " $\"highlight%28x=4%29\"$ \n" ); document.write( "

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