document.write( "Question 96814: log2 (base of 2) of x + 5 (no parentheses) = 8 - log2 (base of 2) of (x+7) \n" ); document.write( "
Algebra.Com's Answer #70435 by stanbon(75887)\"\" \"About 
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log2 x + 5 = 8 - log2 (x+7)
\n" ); document.write( "log2 x + log2 (x+7) = 3
\n" ); document.write( "log2[x(x+7)] = 3
\n" ); document.write( "x(x+7) = 2^3
\n" ); document.write( "x^2+7x = 8
\n" ); document.write( "x^2+7x-8 = 0
\n" ); document.write( "(x-1)(x+8)=0
\n" ); document.write( "x=1 or x= -8
\n" ); document.write( "-----------------------
\n" ); document.write( "Checking these answers in the original equation:
\n" ); document.write( "x cannot be -8 as log2 (-8) is meaningless.
\n" ); document.write( "Checking x=1:
\n" ); document.write( "log2 1 + 5 = 8 - log2 (1+8)
\n" ); document.write( "0 + 5 = 8 - 3
\n" ); document.write( "5 = 5
\n" ); document.write( "x=1 is the only solution
\n" ); document.write( "=======================
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "
\n" );