document.write( "Question 804824: logx+log(x+21)=2 \n" ); document.write( "

Algebra.Com's Answer #484966 by erica65404(394) $\"\"$ $\"About$

You can put this solution on YOUR website!
when you add logs together it is the same as multiplying the numbers u are logging.
\n" ); document.write( "example:
\n" ); document.write( "loga+logb=log(ab)
\n" ); document.write( "You need to do this to this problem
\n" ); document.write( " $\"log%28x%29%2Blog%28x%2B21%29=2\"$
\n" ); document.write( " $\"log%28x%28x%2B21%29%29=2\"$
\n" ); document.write( "when log doesn't have a number where the base should be, it means the base is zero.
\n" ); document.write( "turn this into an exponential equation.
\n" ); document.write( " $\"10%5E2=x%28x%2B21%29\"$
\n" ); document.write( " $\"100=x%5E2%2B21x\"$
\n" ); document.write( " $\"0=x%5E2%2B21x-100\"$
\n" ); document.write( "Now factor the equation.
\n" ); document.write( " $\"%28x-25%29%28x%2B4%29=0\"$
\n" ); document.write( "x= 25, -4 \n" ); document.write( "

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