document.write( "Question 1100499: find x:
\n" ); document.write( "3^x - 3^-x = 4 \n" ); document.write( "

Algebra.Com's Answer #714995 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"3%5Ex-1%2F3%5Ex=4\"$
\n" ); document.write( " $\"3%5E%282x%29-1=4%2A3%5E%282x%29\"$
\n" ); document.write( "Use a substitution,
\n" ); document.write( " $\"u=3%5Ex\"$
\n" ); document.write( " $\"u%5E2=3%5E%282x%29\"$
\n" ); document.write( "So,
\n" ); document.write( " $\"u%5E2-1=4u\"$
\n" ); document.write( " $\"u%5E2-4u-1=0\"$
\n" ); document.write( " $\"u%5E2-4u%2B4-1=4\"$
\n" ); document.write( " $\"%28u-2%29%5E2=5\"$
\n" ); document.write( " $\"u-2=0+%2B-+sqrt%285%29\"$
\n" ); document.write( " $\"u=2+%2B-+sqrt%285%29\"$
\n" ); document.write( " $\"3%5Ex=2+%2B-+sqrt%285%29\"$
\n" ); document.write( "The negative sign would lead to a negative right hand side which is not a possible solution.
\n" ); document.write( " $\"3%5Ex=2%2Bsqrt%285%29\"$
\n" ); document.write( " $\"x=log%283%2C%282%2Bsqrt%285%29%29%29\"$
\n" ); document.write( " $\"highlight%28x=log%28%282%2Bsqrt%285%29%29%29%2Flog%28%283%29%29%29\"$ \r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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