document.write( "Question 631290: log4 (x+16) + log4(x+4) = 3 \n" ); document.write( "

Algebra.Com's Answer #397489 by nerdybill(7384) $\"\"$ $\"About$

You can put this solution on YOUR website!
I'm assuming you meant log base 4:
\n" ); document.write( "log4(x+16) + log4(x+4) = 3
\n" ); document.write( "log4(x+16)(x+4) = 3
\n" ); document.write( "(x+16)(x+4) = 4^3
\n" ); document.write( "x^2+20x+64 = 64
\n" ); document.write( "x^2+20x = 0
\n" ); document.write( "x(x+20) = 0
\n" ); document.write( "x = {-20, 0}
\n" ); document.write( "The -20 won't work (extraneous) throw it out leaving:
\n" ); document.write( "x = 0
\n" ); document.write( " \n" ); document.write( "

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