document.write( "Question 1207302: The lengths of the sides of an equilateral triangle are log4(a), log10(b), log25(a+b) where A and B are positive numbers. What is the value of a/b? \n" ); document.write( "
Algebra.Com's Answer #845094 by greenestamps(13200)\"\" \"About 
You can put this solution on YOUR website!


\n" ); document.write( "Let x be the side length of the equilateral triangle. Then

\n" ); document.write( "\"log%284%2Ca%29=x\" --> \"4%5Ex=a\"

\n" ); document.write( "\"log%2810%2Cb%29=x\" --> \"10%5Ex=b\"

\n" ); document.write( "\"log%2825%2Ca%2Bb%29=x\" --> \"25%5Ex=a%2Bb\"

\n" ); document.write( "Now look for a relationship between the three bases 4, 10, and 25: \"4%2A25+=+10%5E2\". So

\n" ); document.write( "\"%2810%5Ex%29%5E2=b%5E2\"
\n" ); document.write( "\"100%5Ex=b%5E2\"

\n" ); document.write( "\"25%5Ex=%28100%2F4%29%5Ex=100%5Ex%2F4%5Ex\"
\n" ); document.write( "\"a%2Bb=b%5E2%2Fa\"
\n" ); document.write( "\"a%5E2%2Bab=b%5E2\"

\n" ); document.write( "Treat this as a quadratic equation with a as the variable and solve for a using the quadratic formula.

\n" ); document.write( "\"a%5E2%2Bab-b%5E2=0\"

\n" ); document.write( "\"a=%28-b%2Bsqrt%28b%5E2%2B4b%5E2%29%29%2F2\" (ignore the other solution, since a has to be positive)

\n" ); document.write( "\"a=%28-b%2Bsqrt%285b%5E2%29%29%2F2\"

\n" ); document.write( "\"a=%28-b%2Bb%2Asqrt%285%29%29%2F2\"

\n" ); document.write( "\"a=b%28-1%2Bsqrt%285%29%2F2%29\"

\n" ); document.write( "Divide by b to find the value of a/b.

\n" ); document.write( "\"a%2Fb=%28sqrt%285%29-1%29%2F2\"

\n" ); document.write( "ANSWER: \"a%2Fb=%28sqrt%285%29-1%29%2F2\"

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\n" ); document.write( "NOTE added after seeing the response from tutor @ikleyn...

\n" ); document.write( "This provides a good example of how a given problem is open to solving using very different equally good paths.

\n" ); document.write( "ALWAYS be open to the possibility of solving any given problem in different ways. Finding a different (and sometimes better) way to do something is how human knowledge increases.
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