document.write( "Question 35087: log (x+21) + log x = 2 \n" ); document.write( "
Algebra.Com's Answer #21298 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
log (x+21) + log x = 2
\n" ); document.write( "log[x(x+21)]=2
\n" ); document.write( "x(x+21)=10^2=100
\n" ); document.write( "x^2+21x-100=0
\n" ); document.write( "(x+25)(x-4)=0
\n" ); document.write( "x=-25 or x=4
\n" ); document.write( "x=-25 is extraneous as you see if you put that value into the original problem.
\n" ); document.write( "x=4 is a valid solution.
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.\r
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