document.write( "Question 518113: e^4x - 8e^2x - 65 = 0 \n" ); document.write( "

Algebra.Com's Answer #345212 by lwsshak3(11628) $\"\"$ $\"About$

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e^4x - 8e^2x - 65 = 0
\n" ); document.write( "let u=e^2x
\n" ); document.write( "u^2=e^4x
\n" ); document.write( "u^2-8u-65=0
\n" ); document.write( "(u-13)(u+5)=0
\n" ); document.write( "u=13
\n" ); document.write( "or
\n" ); document.write( "u=-5(reject, e^2x>0)
\n" ); document.write( "..
\n" ); document.write( "for u=13
\n" ); document.write( "e^2x=13
\n" ); document.write( "2xlne=ln13
\n" ); document.write( "lne=1
\n" ); document.write( "2x=ln13
\n" ); document.write( "x=ln13/2
\n" ); document.write( "x=1.2825 \n" ); document.write( "

\n" );