document.write( "Question 331639: please help me solve: $\"+log%28+x+%29+%2B+log+%28+%28x-15%29+%29+=+2+\"$ \n" ); document.write( "

Algebra.Com's Answer #237728 by jrfrunner(365) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"+log%28+x+%29+%2B+log+%28+%28x-15%29+%29+=+2+\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"+log%28+x+%29%2A%28x-15%29+=+2+\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"log%28%28x%5E2-15x%29%29+=+2+\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"+10%5E%28log%28x%5E2-15x%29%29+=+10%5E2+\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"+x%5E2-15x+=+100+\"$
\n" ); document.write( " $\"+x%5E2+-+15x+-+100+=0+\"$ factor\r
\n" ); document.write( "\n" ); document.write( "(x-20)*(x+5)=0\r
\n" ); document.write( "\n" ); document.write( "either X=20 or X=-5
\n" ); document.write( "----------------
\n" ); document.write( "check X=20, by substituting in original equation
\n" ); document.write( "Log 20 + log(20-15) =2
\n" ); document.write( "log 20 +log 5=2
\n" ); document.write( " $\"log+20%2A5=log+100=log+10%5E2+=2\"$
\n" ); document.write( "2log10=2
\n" ); document.write( "2=2 verifies X=20 as a solution
\n" ); document.write( "--------------------
\n" ); document.write( "check X=-5
\n" ); document.write( "log(-5)+log(-5-15)=2 STOP!!!! log functions are define for values greater than 0,
\n" ); document.write( "so X=-5 is not a solution\r
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