document.write( "Question 818767: Prove that, 7log16/15+5log25/24+3log81/80=log2. \n" ); document.write( "
Algebra.Com's Answer #492815 by jsmallt9(3758)\"\" \"About 
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\n" ); document.write( "What we will be doing is using properties of logarithms (\"log%28a%2C+%28p%29%29+%2B+log%28a%2C+%28q%29%29+=+log%28a%2C+%28p%2Aq%29%29\", \"log%28a%2C+%28p%29%29+-+log%28a%2C+%28q%29%29+=+log%28a%2C+%28p%2Fq%29%29\" and/or \"n%2Alog%28a%2C+%28p%29%29+=+log%28a%2C+%28p%5En%29%29\") to condense the entire left side into a single logarithm (hopefully log(2)).

\n" ); document.write( "We'll start by using the third property to move the coefficients of each log into its argument as its exponent:
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\n" ); document.write( "Next we can use the first property to combine the three logs:
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\n" ); document.write( "To make simplifying the argument easier, I am going to rewrite each numerator and denominator in terms of prime factors:
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\n" ); document.write( "Now we can use the \"%28a%2Fb%29%5En+=+a%5En%2Fb%5En\" rule to raise each of these fractions to a power:
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\n" ); document.write( "Using the \"a%5En+%2A+a%5Em+=+a%5E%28n%2Bm%29\" rule to multiply the numerators and denominators:
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\n" ); document.write( "The 3's and 5's all cancel out. And we can use the \"a%5En%2Fa%5Em+=+a%5E%28n-m%29\" rule to divide the 2's:
\n" ); document.write( "\"log%28%282%5E%2828-27%29%29%29=log%28%282%29%29%29\"
\n" ); document.write( "\"log%28%282%5E1%29%29=log%28%282%29%29%29\"
\n" ); document.write( "\"log%28%282%29%29=log%28%282%29%29%29\" Check!
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