document.write( "Question 993221: Please help me solve the exponential and logarithmic equation:
\n" ); document.write( "(4^x)-3(4^-x)=8 \n" ); document.write( "

Algebra.Com's Answer #612543 by stanbon(75887) $\"\"$ $\"About$

You can put this solution on YOUR website!
solve the exponential and logarithmic equation:
\n" ); document.write( "(4^x)-3(4^-x)=8
\n" ); document.write( "----------------
\n" ); document.write( "4^x - 3(1/4^x) = 8
\n" ); document.write( "----------
\n" ); document.write( "Multiply thru by 4^x to get::
\n" ); document.write( "(4^x)^2 - 3 = 8(4^x)
\n" ); document.write( "-----
\n" ); document.write( "(4^x)^2 - 8(4^x) - 3 = 0
\n" ); document.write( "------
\n" ); document.write( "Let 4^x = w
\n" ); document.write( "----
\n" ); document.write( "w^2 - 8w - 3 = 0
\n" ); document.write( "---
\n" ); document.write( "w = [8+-sqrt(64-4(-3)]/2
\n" ); document.write( "---
\n" ); document.write( "w = [8+-sqrt(76)]/2
\n" ); document.write( "-----
\n" ); document.write( "Find the positive value of w::
\n" ); document.write( "w = 8.36
\n" ); document.write( "----
\n" ); document.write( "Solve for \"x\"::
\n" ); document.write( "4^x = 8.36
\n" ); document.write( "x = log(8.36)/log(4) = 1.53
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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