document.write( "Question 1196707: log 2 (x-2) + log 2 (x+1) = 2 \n" ); document.write( "

Algebra.Com's Answer #829687 by greenestamps(13206) $\"\"$ $\"About$

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\n" ); document.write( " $\"log%282%2C%28x-2%29%29%2Blog%282%2C%28x%2B1%29%29=2\"$

\n" ); document.write( "A sum of logs is the log of the product:

\n" ); document.write( " $\"log%282%2C%28x%5E2-x-2%29%29=2\"$

\n" ); document.write( " $\"x%5E2-x-2=2%5E2=4\"$
\n" ); document.write( " $\"x%5E2-x-6=0\"$
\n" ); document.write( " $\"%28x-3%29%28x%2B2%29=0\"$
\n" ); document.write( " $\"x=3\"$ or $\"x=-2\"$

\n" ); document.write( "But x = -2 is invalid because we would have to take the logarithm of a negative number.

\n" ); document.write( "ANSWER: x=3

\n" ); document.write( "CHECK:

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